LX470 AHC issues - pressure sensor 1998 Vs. 2002 (2 Viewers)

[IndroCruise]

INDOCRUISE

Thank you for your perseverance, I am almost to the breaking point, but your steadfastness, calmness, and true sincerity keep me going!

In your response, to my post about checking the gears to see if they were turning, that's correct, you CANNOT see them turning at the ends with the cover on. but if you remove it, then oil leaks out the depression area you labeled in post #116. If you take it off, the Oil you put in the top 1" opening where the tank sits, will flow out through that area picture identified in #116 with the labels you provide. Before I forget to tell you, I already installed a NEW seal 90311-10001 where the electric motor shaft connects to the small notched connector! The ONLY seal I have not purchased new, is the Triangular O-ring- I don't know the # number of this one. I can order that locally from a dealer here, but I don't know if its really critical to the pump's ability to work. if you think it IS NECESSARY, then I will order it tomorrow morning. Does this triangular O-ring critical to the operation /pumping ability of this assy? The O-ring and backup ring on the gear shafts that you show in several posts starting in #98 are NEW as they come with the pump sub-assy. so I don't need to replace them and I will be getting NEW ones on the NEW pump that I'm waiting on from IMPEX.
About the only thing I can think of to temporarily seal this " area" that is a cast in depression in the AL housing, is something like simple ... ..... Chewing GUM! I don't have any tiny rubber bungs like I used in the outlet thread area, but I guess I'll try that tomorrow morning!
(PASTE FROM late edit of #115 ) The point of the test is only to see where the fluid is going while also being able to see that the gears are turning -- this cannot be seen while the regular outer cover is in place. I'm not sure I understand your point, or what to infer after this test is performed, but I will do it in the morning. Hopefully, you will see this and comment. I still want to beat this thing and find out WHY THE HECK THIS NEW PUMP WILL NOT PUMP !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Well, its almost midnight CST in TEXAS now, so I will turn in for the evening . I Look forward to hearing from you in the morning Sir!

Well, to refresh my memory, I dis-assembled some of my old spares on the kitchen table -- that was around dinner-time in Brisbane, Australia, so this did not receive a vote of approval from Mrs IndroCruise!!

Firstly, to correct the record -- I found a mistake in the labels on my previous picture in my Post #116 -- which I have edited in that Post. The correct path for AHC Fluid from the Tank to through the Housing to the fluid pick-up point for the AHC Pump sub-assembly is shown in the new labelled picture below. A blockage might be possible here but seems very unlikely at such a large opening -- it is shown in the picture with an Allen key poking through it.

Looking through the check-list (set out as bullet points with explanations way back in my Post #98), it seems you are very well advanced. Summarising that list:

1. Check whether the AHC Electric Motor 88264-60010 is faulty,
2. Check whether the electric motor 88264-60010 is engaging the Pump sub-assembly 48901-60010 properly via small connecting shaft,
3. Check whether AHC Fluid is reaching the Pump sub-assembly 48901-60010,
4. Check whether Air is being drawn into the AHC Pump sub-assembly 48901-60010,
5. Understand the importance in any external gear pump (including the AHC gear pump) of maintaining seals between the high pressure side and the low pressure side within the Pump,
6. Inside the AHC Pump sub-assembly, the relevant seals are:
   • the triangular-looking O-ring under the top-plate,
   • the O-rings on the gearcases,
   • the small O-ring 90301-06012 where the Discharge from AHC Pump sub-assembly joins the Housing 48905-60010 near the Return Valve,
7. Check the seating of the large O-ring at the Outer Cover of the Pump,
8. Check the seating of the grommet between the AHC Tank and the AHC Housing,
9. Check correct position of the “Notch”,
10. Understand the importance of clearing very high pressure fluid emerging from meshed gear teeth,

I think that you should be able to rely on ALL the O-rings (including the triangular O-ring) in the new AHC Pump sub-assembly that you already have installed. Unless you can see damage or distortion, replacement should not be necessary.

If the AHC Pump sub-assembly has been disturbed, I find re-assembly works best if the O-rings AND the back-up rings are inserted into top-plate, not on the gear-carriers, in the gear AHC Pump sub-assembly -- then install the gear-carriers with the “notch” on the Intake side and below the By-pass Strainer in the Pump casing, and then install the top-plate as the last step.

The back-up rings should be in contact with the top-plate; the O-rings should be in contact with the gear-carriers.

The above method seems to avoid any unseen twisting of the O-rings when the top-plate is installed. The gears should not be difficult to turn with the fingers when the top-plate has been installed if all has gone well. Twisted or deformed O-rings will be indicated by gears being hard to turn with the fingers. Leakage and pressure loss are likely with deformed or badly seated O-rings.

As @suprarx7nut also mentions, it is important to make sure that the gears actually are turning when the Motor operates. Even with the Outer Cover removed as I have suggested, this can be difficult to see because only a glimpse of the very top of each gear-spindle can be seen. The gear-carriers do not rotate. There will be a little leakage at the top of the gear-spindles because they are not behind the O-rings. If there is major leakage at this point, problems with the O-rings at the gear-carriers have to be suspected -- and this most likely means new O-rings are required as experienced by @BullElk -- or start again with a new AHC Pump sub-assembly.

Suggest first check that the small steel connecting shaft between the Motor and the Pump has not become dislodged. Suggest use a screw-driver to turn the connector before installing the AHC Pump sub-assembly and ensure that the Motor is turning -- the Motor should feel “lumpy” when turned as the brushes pass over each segment of the commutator and make and break each Motor circuit in turn.

If after all of this, and even after installing a brand new (unopened) replacement AHC Pump sub-assembly, no flow or weak pressure is still experienced at the Discharge with no pipe attached at the Overall Pump Assembly (next to the Pressure Sensor), then that may suggest a problem or a blockage at or around the Return Valve.

In such a case, and looking at the hydraulic circuit back at Post #115 and elswehere, it may be worthwhile to remove the Pressure Sensor and run the Pump -- strong flow should then emerge from the Pressure Sensor aperture -- that should show whether the Pump is running properly and also help in determining whether there is a problem at or around the Return Valve. Let's hope that there is no such problem -- it would be EXTREMELY unusual!!

Hopefully there will be success and that this will include elimination of the DTC C1762 problem!! However, as is well-understood, there can be other causes of the DTC C1762 -- especially given that there will be air in the system as a result of this work and previous work.

It seems likely that a major repetitive effort to bleed and flush air will be required when the problems with the AHC Pump have been overcome, as discussed way back with others, including @2001LC .

Anyway, hope all goes well today!!!!!!!

 

[suprasvobodea]

Ok. It’s the simple stuff that sometimes gets missed, especially after months of trying everything. I’ll check it out this morning and report back

View attachment 3654756

UPDATE >>> 6-14 9:30 AM
I removed the cover and poured oil into the area shown with an arrow( I don't have a text option when editing with this photo app) . I held it at an angle to maintain a small "pool " of oil in that cavity. When I applied 12V , IT DID NOT GO LOWER WHICH MEANS it's NOT PUMPING ANYTHING!. I removed the black rubber bung, and nothing came out (except leakage drips) .
I looked at the end of the gear shafts and they WERE SPINNING! So it is engaging, .. it's just not acting like a pump!!! The 4 Allen screws are torqued down very tightly, and there was NO seepage around the perimeter of the pump halves. so the new pump is NOT leaking (visibly) . Oh, I also removed the return access( Large Allen screw) that allows access to the 3rd screen and removed it with a screw -just like in the 3rd picture in #115 from INDOCRUISE, and it was clean as new. - so there is no blockage there either.
So, I have a new pump assy, that has spinning gears, but not moving any fluid thru it. It has all new o-rings except for the one that forms a triangle.! I will order that O-ring as well, but I don't know the part number. If anyone has this, please let me know.
Otherwise, I don know what else to do, except wait for another new pump assy to arrive from IMPEX,.... sometime in the future -( they have the absolute LOWEST prices on these kinds of parts ( the equivalent price in the states online is $419-489 dollars!)

The frightening thing is, All I did was open the thing up to check the little screens after I installed it and removed it when I was still getting the damn 1762 error code.

 

[IndroCruise]

Beyond the ideas mentioned in my Post #121, (such as running the Pump with the Pressure Sensor removed), it does seem that the best next step is to use another AHC Pump sub-assembly.

However ....

A new Pump is in the vehicle with good O-rings and seals everywhere -- and given that you wanted this vehicle going today, would it be worth trying new O-rings on the gear-carriers anyway??

I don't know the size specification --- this may mean buying several sizes to see what fits best, really just copying the recent story by @BullElk . Assume the back-up rings are OK.

This might be the last roll of the dice -- but it may be better than waiting??

Unless there are better ideas anywhere ....

 

[BullElk]

Beyond the ideas mentioned in my Post #121, (such as running the Pump with the Pressure Sensor removed), it does seem that the best next step is to use another AHC Pump sub-assembly.

However ....

A new Pump is in the vehicle with new O-rings and seals everywhere -- and given that you wanted this vehicle going today, would it be worth trying new O-rings on the gear-carriers anyway??

I don't know the size specification --- this may mean buying several sizes to see what fits best, really just copying the recent story by @BullElk . Assume the back-up rings are OK.

This might be the last roll of the dice -- but it may be better than waiting??

Unless there are better ideas anywhere ....

Yes I went thru this same relentless situation. Thinking that the only thing inside that block of aluminum that could go wrong was the O rings, I picked up a box of like 200 assorted O rings from Harbor Freight to try. I used ones that seemed to be correct total diameter but the ring was just a bit fatter and still fit side by side on the two gears.

Cranked truck and pump created pressure. At one point since then it didn’t hold pressure but since then it seems to be doing very well.

 

[suprasvobodea]

Beyond the ideas mentioned in my Post #121, (such as running the Pump with the Pressure Sensor removed), it does seem that the best next step is to use another AHC Pump sub-assembly.

However ....

A new Pump is in the vehicle with new O-rings and seals everywhere -- and given that you wanted this vehicle going today, would it be worth trying new O-rings on the gear-carriers anyway??

I don't know the size specification --- this may mean buying several sizes to see what fits best, really just copying the recent story by @BullElk . Assume the back-up rings are OK.

This might be the last roll of the dice -- but it may be better than waiting??

Unless there are better ideas anywhere ....

I have a full service hardware store that actually stocks metrics-O rings . I have a digital vernier caliper too . I’m going to get measurements on thickness & dia in mm,& get O rings for 2 gear shafts & the triangle shaped tomorrow morning.
I’ll also remove PS ftom assy. , & apply 12 V & see what happens & report back in morning
I’m just too curious as well as frustrated as to WHY TNIS THING WONT PUMP !

 

[IndroCruise]

I have a full service hardware store that actually stocks metrics-O rings . I have a digital vernier caliper too . I’m going to get measurements on thickness & dia in mm,& get O rings for 2 gear shafts & the triangle shaped tomorrow morning.
I’ll also remove PS ftom assy. , & apply 12 V & see what happens & report back in morning
I’m just too curious as well as frustrated as to WHY TNIS THING WONT PUMP !

Maybe also even try operating the Pump with the "Notch" in the opposite position as suggested by @Moridinbg from his experience with an old Pump?? Personally I cannot understand how or why this could work in new Pump but nothing is lost by trying this. Although I think maybe you already tried this arrangement without success??

 

[IndroCruise]

Maybe also even try operating the Pump with the "Notch" in the opposite position as suggested by @Moridinbg from his experience with an old Pump?? Personally I cannot understand how or why this could work in new Pump but nothing is lost by trying this. Although I think maybe you already tried this arrangement without success??

.... or maybe longtimers such as @PADDO and @uHu or any others might have some different insights??

 

[BullElk]

If there is major leakage at this point, problems with the O-rings at the gear-carriers have to be suspected -- and this most likely means new O-rings are required as experienced by @BullElk --

For the record and transparency for higher learning….
I absolutely do think tight and properly seated O rings are a or the key factor in the pump sealing off resistance and creating the pressure needed to do the suspension job intended.

However, mine is acting up again but only when loading down with overlanding gear. So I guess a few hundred extra pounds and rear decided to go to the bump stops only after I pressed UP. I could tell it didn’t want to go up so I pressed down real fast and it just kept going down forever.

Then the motor acted like it was struggling and not producing any pressure at all, even when providing direct power to motor. I also jump pins to activate pump with no luck. Basically exactly the same issue I had before when I changed O rings.

So 10 hours away in the Carolina mountains, I’m bump stop bouncing in the rear. We stop at a town to galavant a while, crank LX to leave and pump came to life just a bit and put a little fluid to the rear. Now it’s in a high sensor LOW. Not perfect but lots smoother and not bump stopping. But who knows what it will do tomorrow.

It seems like perhaps the fluid may be escaping past the O rings but getting some presume intermittently. I also wonder if temperature may be a factor.

I already have LC torsion bars, rear OME springs and ordered four new OEM shocks today. For my ‘06 LX ONLY, which is specifically used for long overlanding trips, I am now in the camp of….I’ve fought my last battle with AHC and switching to the static suspension way of life.

For my other four Lexii, I am still a big AHC fan man. Now with a few spare parts.

 

[IndroCruise]

It seems like perhaps the fluid may be escaping past the O rings but getting some presume intermittently. I also wonder if temperature may be a factor.

Maybe as above -- no question about the importance of the seals between the high pressure side and the low pressure side of any gear pump -- meanng the O-rings on the gear carriers in the case of the AHC Pump -- but reflecting on various AHC-related threads and experiences on which @suprarx7nut, @2001LC and @Moridinbg have reported, cannot help the feeling that intermittency may be more related to harness / wiring issues rather than hydraulic issues, specifically a loose or damaged wire which randomly makes or breaks continuity??

 

[BullElk]

Maybe as above -- no question about the importance of the seals between the high pressure side and the low pressure side of any gear pump -- meanng the O-rings on the gear carriers in the case of the AHC Pump -- but reflecting on various AHC-related threads and experiences on which @suprarx7nut, @2001LC and @Moridinbg have reported, cannot help the feeling that intermittency may be more related to harness / wiring issues rather than hydraulic issues, specifically a loose or damaged wire which randomly makes or breaks continuity??

Makes sense but my issue happens only when adding overlanding/camping gear, spreading the weight out from front seats and back.

 

[suprasvobodea]

Maybe also even try operating the Pump with the "Notch" in the opposite position as suggested by @Moridinbg from his experience with an old Pump?? Personally I cannot understand how or why this could work in new Pump but nothing is lost by trying this. Although I think maybe you already tried this arrangement without success??

<<<UPDATE 7/4/24 - 4th of JUly Holiday Celebration


Finally , got a NEW PUMP ASSY that i DID NOT OPEN and installed on the assy. I primed it first by pouring a little opening in the intake area, and tilting it untill all the bubbles stoped. Then i tapped the round cover several times just to make sure.
THen attached the tank to the whole assy , filled the tank 1/2 full of new oil, and manuall applied 12V to the pump motor. It pushed out a stream of oil!! HOWEVER... and this is a big one ........... Has ANYONE EVER TRIED TO BLOCK THE OUTFLOW WITH THIER FINGER/THUMB LIKE YOU WOULD ON A GARDEN HOSE???? I need to know for sure, as i was able to prevent the outlet flow with my finger!!! I then removed the new PS on the unit, applied 12V and it pumped out alot of oil!
SO... we know the NEW pump works, however its still throwing the 1762 code.

I also manually operated the pump , WHILE applying 12 V to the accumulator solenoid ( just powerign the pump WILL NOT allow oil to fill the accumulator - i thin this is per INDOCRUISE ) I DID get some oil to fill the acculator this way and bleed out the air that was inssyteem after installing the new pump and connecting the outlet SS line. I also bled the LF globe and the other 3 ( VERY little came out since there is no pressure in system due to 1762 code)
AFTER ALL THIS , Im still getting the 1762!!! :-(

So,........... whats next ..? Its been several months now that i have not driven my LX!! Im out of time , patience and things to yet try. I need to the answer to the fail safe protect issue here. Is it electrical or pressure ( air) releated?? Please ,, any one with a suggestion or question .. PLEASE HELP

 

[IndroCruise]

Please do not use a white font -- it does not show up on a white screen -- delays any response. I have pasted your last post here in good ole black-and-white so all can read -- except for the IMPORTANT DETAIL which I highlighted in RED BOLD:

++++++++++++++++
<<<UPDATE 7/4/24 - 4th of JUly Holiday Celebration

Finally , got a NEW PUMP ASSY that i DID NOT OPEN and installed on the assy. I primed it first by pouring a little opening in the intake area, and tilting it untill all the bubbles stoped. Then i tapped the round cover several times just to make sure.
THen attached the tank to the whole assy , filled the tank 1/2 full of new oil, and manuall applied 12V to the pump motor. It pushed out a stream of oil!! HOWEVER... and this is a big one ........... Has ANYONE EVER TRIED TO BLOCK THE OUTFLOW WITH THIER FINGER/THUMB LIKE YOU WOULD ON A GARDEN HOSE???? I need to know for sure, as i was able to prevent the outlet flow with my finger!!! I then removed the new PS on the unit, applied 12V and it pumped out alot of oil!
SO... we know the NEW pump works, however its still throwing the 1762 code.
I also manually operated the pump , WHILE applying 12 V to the accumulator solenoid ( just powerign the pump WILL NOT allow oil to fill the accumulator - i thin this is per INDOCRUISE ) I DID get some oil to fill the acculator this way and bleed out the air that was inssyteem after installing the new pump and connecting the outlet SS line. I also bled the LF globe and the other 3 ( VERY little came out since there is no pressure in system due to 1762 code)
AFTER ALL THIS , Im still getting the 1762!!! :-(

So,........... whats next ..? Its been several months now that i have not driven my LX!! Im out of time , patience and things to yet try. I need to the answer to the fail safe protect issue here. Is it electrical or pressure ( air) releated?? Please ,, any one with a suggestion or question .. PLEASE HELP
++++++++++++++++++++++++++++

So .....

"I then removed the new PS (Pressure Sensor) on the unit, applied 12V and it pumped out alot of oil!"

This was suggested back at post #121 and post #123 this thread without needing to wait for the new AHC Pump.

Please describe what happened when you operated the AHC Pump with the Pressure Sensor removed.

Was the flow at the Pressure Sensor position with the Pressure Sensor removed stronger than at the normal discharge point which you could stop with finger pressure?

Did you try stopping the flow at the outlet with Pressure Sensor removed with your finger or thumb?

This detail is important. The point of the suggestion is to make sure that the AHC Pump is delivering normally and that there is no obstruction at the Return Valve, extremely unusual as this may be. Yes, you have advised previously that you have checked the strainer at the Return Valve but that does NOT confirm the operation of the Return Valve.

If the flow from the AHC Pump can be stopped with a finger, then something is wrong, either mechanically or in the fitting procedures.

It is difficult to imagine how the pressure of a normally operating healthy AHC pump sub-assembly could be stopped by the pressure of a finger. In a healthy vehicle the AHC Pump participates continuously in automatic self-levelling, working against the AHC system pressure of +/- 6Mpa. The AHC Pump also recharges the Height Control Accumulator to around 10.5MPa after a raise from LO to N or a raise from N to HI. If the Height Control Accumulator is empty, then the AHC Pump raises the vehicle directly, but slowly.

As has been stated many times, installing a new AHC Pump sub-assembly will NOT by itself overcome a DTC C1762 condition. There IS air in the system in this vehicle because it has been opened for various changes and replacements. Repetitive bleeding attempts over and over and over again will be required.

When you think that the AHC Pump is capable of developing pressure, then you will need to ....

-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,

Repeat over and over and over again -- this is a tedious "inching" process which attempts to increase the AHC system pressure and raise the vehicle little by little, recognising that the DTC C1762 will be activated repeatedly until sufficient pressure is developed.

Air in the system is the most common cause of DTC C1762 -- it occurs because pressure cannot be developed quickly enough (within 0.6 seconds) and DTC C1762 is triggered.

With a bleeder open, pressure will not be developed and DTC C1762 will persist. The idea is to keep the distant bleeder screw open for a few times to allow Fluid and as much Air as possible to escape, then close the bleeder screw and attempt to build pressure in repetitive attempts.

This all assumes that the AHC electrical circuits between sensors everywhere and the ECU are healthy and have continuity to the ECU. As highlighted by @2001LC in earlier posts in this thread and elsewhere, loss of continuity due to a loose or broken wire can result in similar symptoms. If VERY persistent and repeated bleeding attempts are unsuccessful, then -- but not before then -- it is time to investigate wiring issues.

First, it is important to discover why neither the old AHC Pump nor the new AHC Pump are delivering the expected pressure and flow. If some data would help, attaching a pressure gauge could be considered (such as the LSPV gauge used for brakes and also used on the AHC system when Techstream is not available). The gauge would be attached in place of the pipe at the delivery point on the housing next to the AHC Pump. In this way, the actual AHC Pump pressure developed when dead-heading could be measured -- although it has to be said that the 'finger test' should be good enough.

Here are a few more pictures - now with Late Edits to correct labels - some are mine and some are borrowed from Club Lexus in Russia, showing details of the Return Valve:

Extracting the Return Valve:

View of Return Valve after extraction -- also showing strainer at the Return Valve:

FSM explanation of the operation of the Return Valve:

AHC Return Valve Check -- with direct 12 volt connection to Pump Motor:

 

[IndroCruise]

++++++++++++++++
<<<UPDATE 7/4/24 - 4th of JUly Holiday Celebration

Finally , got a NEW PUMP ASSY that i DID NOT OPEN and installed on the assy. I primed it first by pouring a little opening in the intake area, and tilting it untill all the bubbles stoped. Then i tapped the round cover several times just to make sure.
THen attached the tank to the whole assy , filled the tank 1/2 full of new oil, and manuall applied 12V to the pump motor. It pushed out a stream of oil!! HOWEVER... and this is a big one ........... Has ANYONE EVER TRIED TO BLOCK THE OUTFLOW WITH THIER FINGER/THUMB LIKE YOU WOULD ON A GARDEN HOSE???? I need to know for sure, as i was able to prevent the outlet flow with my finger!!! I then removed the new PS on the unit, applied 12V and it pumped out alot of oil!
SO... we know the NEW pump works, however its still throwing the 1762 code.
I also manually operated the pump , WHILE applying 12 V to the accumulator solenoid ( just powerign the pump WILL NOT allow oil to fill the accumulator - i thin this is per INDOCRUISE ) I DID get some oil to fill the acculator this way and bleed out the air that was inssyteem after installing the new pump and connecting the outlet SS line. I also bled the LF globe and the other 3 ( VERY little came out since there is no pressure in system due to 1762 code)
AFTER ALL THIS , Im still getting the 1762!!! :-(

So,........... whats next ..? Its been several months now that i have not driven my LX!! Im out of time , patience and things to yet try. I need to the answer to the fail safe protect issue here. Is it electrical or pressure ( air) releated?? Please ,, any one with a suggestion or question .. PLEASE HELP
++++++++++++++++++++++++++++

So .....

"I then removed the new PS (Pressure Sensor) on the unit, applied 12V and it pumped out alot of oil!"

This was suggested back at post #121 and post #123 this thread without needing to wait for the new AHC Pump.

Please describe what happened when you operated the AHC Pump with the Pressure Sensor removed.

Was the flow at the Pressure Sensor position with the Pressure Sensor removed stronger than at the normal discharge point which you could stop with finger pressure?

Did you try stopping the flow at the outlet with Pressure Sensor removed with your finger or thumb?

This detail is important. The point of the suggestion is to make sure that the AHC Pump is delivering normally and that there is no obstruction at the Return Valve, extremely unusual as this may be. Yes, you have advised previously that you have checked the strainer at the Return Valve but that does NOT confirm the operation of the Return Valve.

If the flow from the AHC Pump can be stopped with a finger, then something is wrong, either mechanically or in the fitting procedures.

It is difficult to imagine how the pressure of a normally operating healthy AHC pump sub-assembly could be stopped by the pressure of a finger. In a healthy vehicle the AHC Pump participates continuously in automatic self-levelling, working against the AHC system pressure of +/- 6Mpa. The AHC Pump also recharges the Height Control Accumulator to around 10.5MPa after a raise from LO to N or a raise from N to HI. If the Height Control Accumulator is empty, then the AHC Pump raises the vehicle directly, but slowly.

As has been stated many times, installing a new AHC Pump sub-assembly will NOT by itself overcome a DTC C1762 condition. There IS air in the system in this vehicle because it has been opened for various changes and replacements. Repetitive bleeding attempts over and over and over again will be required.

When you think that the AHC Pump is capable of developing pressure, then you will need to ....

-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,

Repeat over and over and over again -- this is a tedious "inching" process which attempts to increase the AHC system pressure and raise the vehicle little by little, recognising that the DTC C1762 will be activated repeatedly until sufficient pressure is developed.

Air in the system is the most common cause of DTC C1762 -- it occurs because pressure cannot be developed quickly enough (within 0.6 seconds) and DTC C1762 is triggered.

With a bleeder open, pressure will not be developed and DTC C1762 will persist. The idea is to keep the distant bleeder screw open for a few times to allow Fluid and as much Air as possible to escape, then close the bleeder screw and attempt to build pressure in repetitive attempts.

This all assumes that the AHC electrical circuits between sensors everywhere and the ECU are healthy and have continuity to the ECU. As highlighted by @2001LC in earlier posts in this thread and elsewhere, loss of continuity due to a loose or broken wire can result in similar symptoms. If VERY persistent and repeated bleeding attempts are unsuccessful, then -- but not before then -- it is time to investigate wiring issues.

First, it is important to discover why neither the old AHC Pump nor the new AHC Pump are delivering the expected pressure and flow. If some data would help, attaching a pressure gauge could be considered (such as the LSPV gauge used for brakes and also used on the AHC system when Techstream is not available). The gauge would be attached in place of the pipe at the delivery point on the housing next to the AHC Pump. In this way, the actual AHC Pump pressure reached when dead-heading could be measured -- although it has to be said that the 'finger test' should be good enough.

Here are a few more pictures - now with Late Edits to correct labels - some are mine and some are borrowed from Club Lexus in Russia, showing details of the Return Valve:

View attachment 3670702
Extracting the Return Valve:
View attachment 3670703

View of Return Valve after extraction -- also showing strainer at the Return Valve:
View attachment 3670704

FSM explanation of the operation of the Return Valve:
View attachment 3670708

AHC Return Valve Check:
View attachment 3670835

^^^^^ Late Edits and pictures added in previous Post

 

[suprarx7nut]

<<<UPDATE 7/4/24 - 4th of JUly Holiday Celebration


Finally , got a NEW PUMP ASSY that i DID NOT OPEN and installed on the assy. I primed it first by pouring a little opening in the intake area, and tilting it untill all the bubbles stoped. Then i tapped the round cover several times just to make sure.
THen attached the tank to the whole assy , filled the tank 1/2 full of new oil, and manuall applied 12V to the pump motor. It pushed out a stream of oil!! HOWEVER... and this is a big one ........... Has ANYONE EVER TRIED TO BLOCK THE OUTFLOW WITH THIER FINGER/THUMB LIKE YOU WOULD ON A GARDEN HOSE???? I need to know for sure, as i was able to prevent the outlet flow with my finger!!! I then removed the new PS on the unit, applied 12V and it pumped out alot of oil!
SO... we know the NEW pump works, however its still throwing the 1762 code.

I also manually operated the pump , WHILE applying 12 V to the accumulator solenoid ( just powerign the pump WILL NOT allow oil to fill the accumulator - i thin this is per INDOCRUISE ) I DID get some oil to fill the acculator this way and bleed out the air that was inssyteem after installing the new pump and connecting the outlet SS line. I also bled the LF globe and the other 3 ( VERY little came out since there is no pressure in system due to 1762 code)
AFTER ALL THIS , Im still getting the 1762!!! :-(

So,........... whats next ..? Its been several months now that i have not driven my LX!! Im out of time , patience and things to yet try. I need to the answer to the fail safe protect issue here. Is it electrical or pressure ( air) releated?? Please ,, any one with a suggestion or question .. PLEASE HELP

Forget the garden hose data point. Forget it entirely. Your new pump should work just fine. We don't know how that should behave so it's not a valid data point. Move on...

Forget the accumulator. That will fill on it's own later. It's only a distraction right now. Forget it. If it's not open, then it's not contributing to the 1762 code.

You installed the new pump. You filled the reservoir. You applied power and ran the pump and some fluid moved in the system. SUCCESS! You bled some fluid out. DO THIS AGAIN. AND AGAIN. AND AGAIN. And then *literally* 97 more times. You should spend hours doing this before you look to any other soluiton.

Power the pump, bleed. Power the pump, bleed. Over and over and over. And over and over and over.

 

[medtro]

When you think that the AHC Pump is capable of developing pressure, then you will need to ....

-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,

Is this done with engine running? When is a good time to close the furthest bleeder?

 

[suprasvobodea]

++++++++++++++++
<<<UPDATE 7/4/24 - 4th of JUly Holiday Celebration

Finally , got a NEW PUMP ASSY that i DID NOT OPEN and installed on the assy. I primed it first by pouring a little opening in the intake area, and tilting it untill all the bubbles stoped. Then i tapped the round cover several times just to make sure.
THen attached the tank to the whole assy , filled the tank 1/2 full of new oil, and manuall applied 12V to the pump motor. It pushed out a stream of oil!! HOWEVER... and this is a big one ........... Has ANYONE EVER TRIED TO BLOCK THE OUTFLOW WITH THIER FINGER/THUMB LIKE YOU WOULD ON A GARDEN HOSE???? I need to know for sure, as i was able to prevent the outlet flow with my finger!!! I then removed the new PS on the unit, applied 12V and it pumped out alot of oil!
SO... we know the NEW pump works, however its still throwing the 1762 code.
I also manually operated the pump , WHILE applying 12 V to the accumulator solenoid ( just powerign the pump WILL NOT allow oil to fill the accumulator - i thin this is per INDOCRUISE ) I DID get some oil to fill the acculator this way and bleed out the air that was inssyteem after installing the new pump and connecting the outlet SS line. I also bled the LF globe and the other 3 ( VERY little came out since there is no pressure in system due to 1762 code)
AFTER ALL THIS , Im still getting the 1762!!! :-(

So,........... whats next ..? Its been several months now that i have not driven my LX!! Im out of time , patience and things to yet try. I need to the answer to the fail safe protect issue here. Is it electrical or pressure ( air) releated?? Please ,, any one with a suggestion or question .. PLEASE HELP
++++++++++++++++++++++++++++

So .....

"I then removed the new PS (Pressure Sensor) on the unit, applied 12V and it pumped out alot of oil!"

This was suggested back at post #121 and post #123 this thread without needing to wait for the new AHC Pump.

Please describe what happened when you operated the AHC Pump with the Pressure Sensor removed. UPDATE 7/7 >> I just removed the new PS again and this time i used a gloved thumb over the outlet when i applied 12V+ to the pump. It pushed alot of fluid. THEN ... I covered the outlet with my thumb and WOW!!!!! I COULD NOT HOLD THE FLUID BACK (dead head it) like i could with the outlet!! I tried again and it just sprayed all over the place! SO........ maybe this explains why i am NOT GETTING pressure from the outlet! How can I prevent ANY fluid coming out from the outlet with the brake line fitting removed by just covering it with my finger! NEXT QUESTION INDOCRUISE...... Should i remove the pump again and disasseble the sub assy to remove the screen again? I saw your pictures from the Russia post., but i do not know how to remove the RETURN VALVE ? Is it unscrewed or what..? If i removed the check the screen a month ago, ( but not the return valve) what should i do? Can this return valve become plugged and un -usable? Do i have to order this part now too ? If so , what is the part number?

Please let me know this afternoon or tonight - ASAP if possible. I want to hear what you have to say BEFORE I go thru 100's of cycles of 1682 trouble codes and bleeds, and a jumping the dia box to run the ACTIVE TEST 90 + times. If the outlet pressure is just a few PSI and I can hold back the oil with my finger when it's running, there IS NO WAY THIS system is going TO WORK! I need to diagnose this issue FIRST! PLEASE LET ME KNOW ASAP -

Was the flow at the Pressure Sensor position with the Pressure Sensor removed stronger than at the normal discharge point which you could stop with finger pressure? YES!! It was spraying all over the place when i tried to deadhead it with my thumb. I could not stop it ( which is normal and shows it the new pump works!)

Did you try stopping the flow at the outlet with Pressure Sensor removed with your finger or thumb? ( YES - see answer above)

This detail is important. The point of the suggestion is to make sure that the AHC Pump is delivering normally and that there is no obstruction at the Return Valve, extremely unusual as this may be. Yes, you have advised previously that you have checked the strainer at the Return Valve but that does NOT confirm the operation of the Return Valve. THIS BEGS THE QUESTION..... now that i have proven that the flow cannot be stopped at the PS location, but i CAN stop it with my thumb at the outlet..... what next ? As i stated earlier, I DID remove the strainer and it was clean. Now, i thinki i need to dissemble the whole unit again, and remove the Hex head screw, pull out the strainer. THen , how is the bypass valve removed ? Is this the next step?

If the flow from the AHC Pump can be stopped with a finger, then something is wrong, either mechanically or in the fitting procedures. YES, i agree. But what ..?

It is difficult to imagine how the pressure of a normally operating healthy AHC pump sub-assembly could be stopped by the pressure of a finger. In a healthy vehicle the AHC Pump participates continuously in automatic self-levelling, working against the AHC system pressure of +/- 6Mpa. The AHC Pump also recharges the Height Control Accumulator to around 10.5MPa after a raise from LO to N or a raise from N to HI. If the Height Control Accumulator is empty, then the AHC Pump raises the vehicle directly, but slowly. I agree. SO,.. what is the problem? EVerything is new and replaced. The part 48905-60010 is $800 and i cannot afford this , its just a close tolerance machined plate of AL, with a bypass valve!

As has been stated many times, installing a new AHC Pump sub-assembly will NOT by itself overcome a DTC C1762 condition. There IS air in the system in this vehicle because it has been opened for various changes and replacements. Repetitive bleeding attempts over and over and over again will be required.

When you think that the AHC Pump is capable of developing pressure, then you will need to ....

-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,
-- press UP switch with furthest bleeder open (driver side rear),
-- bleed,
-- receive DTC C1762,
-- clear the DTC,

Repeat over and over and over again -- this is a tedious "inching" process which attempts to increase the AHC system pressure and raise the vehicle little by little, recognising that the DTC C1762 will be activated repeatedly until sufficient pressure is developed.

Air in the system is the most common cause of DTC C1762 -- it occurs because pressure cannot be developed quickly enough (within 0.6 seconds) and DTC C1762 is triggered.

With a bleeder open, pressure will not be developed and DTC C1762 will persist. The idea is to keep the distant bleeder screw open for a few times to allow Fluid and as much Air as possible to escape, then close the bleeder screw and attempt to build pressure in repetitive attempts.

This all assumes that the AHC electrical circuits between sensors everywhere and the ECU are healthy and have continuity to the ECU. As highlighted by @2001LC in earlier posts in this thread and elsewhere, loss of continuity due to a loose or broken wire can result in similar symptoms. If VERY persistent and repeated bleeding attempts are unsuccessful, then -- but not before then -- it is time to investigate wiring issues.

First, it is important to discover why neither the old AHC Pump nor the new AHC Pump are delivering the expected pressure and flow. If some data would help, attaching a pressure gauge could be considered (such as the LSPV gauge used for brakes and also used on the AHC system when Techstream is not available). The gauge would be attached in place of the pipe at the delivery point on the housing next to the AHC Pump. In this way, the actual AHC Pump pressure developed when dead-heading could be measured -- although it has to be said that the 'finger test' should be good enough.

Here are a few more pictures - now with Late Edits to correct labels - some are mine and some are borrowed from Club Lexus in Russia, showing details of the Return Valve:

View attachment 3670702
Extracting the Return Valve:
View attachment 3670703

View of Return Valve after extraction -- also showing strainer at the Return Valve:
View attachment 3670704

FSM explanation of the operation of the Return Valve:
View attachment 3670708

AHC Return Valve Check -- with direct 12 volt connection to Pump Motor:
View attachment 3670835

UPDATE>> July 4th - response to your latest respose

INDOCRUISE- I have responded to your questions about the new PS and outlet pressure output above in BLUE

 

[suprasvobodea]

Forget the garden hose data point. Forget it entirely. Your new pump should work just fine. We don't know how that should behave so it's not a valid data point. Move on...

Forget the accumulator. That will fill on it's own later. It's only a distraction right now. Forget it. If it's not open, then it's not contributing to the 1762 code.

You installed the new pump. You filled the reservoir. You applied power and ran the pump and some fluid moved in the system. SUCCESS! You bled some fluid out. DO THIS AGAIN. AND AGAIN. AND AGAIN. And then *literally* 97 more times. You should spend hours doing this before you look to any other soluiton.

Power the pump, bleed. Power the pump, bleed. Over and over and over. And over and over and over.

SupraRX7 nit

UPDATE 7/7/24>>
I removed the new PS and applied 12V to the pump and it pushed out a lot of oil. Then I coved the outlet with a gloved thumb and I COULD NOT STOP THE FLOW .. IT SPRAYED ALL OVER THE passenger side engine block! (like I would expect it to) When I reinstalled the PS and removed the outlet line from the pump, & applied 12V to the pump directly, I could prevent OIL FROM ESCAPING FROM THE PUMP UNIT simply by covering the outlet with my finger! I think I need to know and diagnose this FIRST, before trying 97+ to bleed the system, open the driver-side rear globe, clearing the 1762 code, 100 times.

How is it possible for high-pressure oil to exist from the PS location when removed, but it's just a stream from the outlet, that I can block by simply covering the hole with my finger .....?
Answer >>> Per the diagrams from INDOCRUISE, it has got to be something in line with the return valve. It's the next thing in the fluid path before the exit from the pump!!!!! Should I remove the assy from the LX again, and disassemble it and try to remove the return valve? I did remove the screen fir the return valve and it was clear. All I can think of is the valve itself is not functioning or blocked.

 

[suprarx7nut]

SupraRX7 nit

UPDATE 7/7/24>>
I removed the new PS and applied 12V to the pump and it pushed out a lot of oil. Then I coved the outlet with a gloved thumb and I COULD NOT STOP THE FLOW .. IT SPRAYED ALL OVER THE passenger side engine block! (like I would expect it to) When I reinstalled the PS and removed the outlet line from the pump, & applied 12V to the pump directly, I could prevent OIL FROM ESCAPING FROM THE PUMP UNIT simply by covering the outlet with my finger! I think I need to know and diagnose this FIRST, before trying 97+ to bleed the system, open the driver-side rear globe, clearing the 1762 code, 100 times.

How is it possible for high-pressure oil to exist from the PS location when removed, but it's just a stream from the outlet, that I can block by simply covering the hole with my finger .....?
Answer >>> Per the diagrams from INDOCRUISE, it has got to be something in line with the return valve. It's the next thing in the fluid path before the exit from the pump!!!!! Should I remove the assy from the LX again, and disassemble it and try to remove the return valve? I did remove the screen fir the return valve and it was clear. All I can think of is the valve itself is not functioning or blocked.

Just guessing, but I don't expect the return valve to be your issue.

Your finger over the outlet tests hold little weight for me because I don't know anyone that's tested that to establish normal operation. I understand your thought process in that you'd expect it to be hard to hold back flow. However, without knowing how that normally operates in the "Garden Hose" test, I can't really say what's a pass or fail.

I'd keep applying power and see if you can get any fluid movement.

 

[IndroCruise]

Please let me know this afternoon or tonight - ASAP if possible. I want to hear what you have to say BEFORE I go thru 100's of cycles of 1682 trouble codes and bleeds, and a jumping the dia box to run the ACTIVE TEST 90 + times. If the outlet pressure is just a few PSI and I can hold back the oil with my finger when it's running, there IS NO WAY THIS system is going TO WORK! I need to diagnose this issue FIRST! PLEASE LET ME KNOW ASAP -



UPDATE>> July 4th - response to your latest respose

INDOCRUISE- I have responded to your questions about the new PS and outlet pressure output above in BLUE

Mmmmm – best if expressions like “begs the question” and some other blue comments are put down to very understandable frustrations!!

Why is “Active Test” still appearing?? There have been multiple mentions of why that does not work when faced with DTC C1762.

You have been taken to the Return Valve in multiple Posts with diagnostic ideas and with diagrams and pictures on how to proceed over a period of almost 4 weeks – see my posts: June 13, 2024 at Post #115; June 15, 2024 in Post #121; July 4, 2024 in Post #131; July 6, 2024 in Post #132 – INCLUDING sufficient pictures on how to remove and examine the Return Valve.

On July 8, 2024 in your Post #136, you have provided a clear answer that the recommended test had been performed and which confirms high pressure and flow from the AHC Pump sub-assembly 48901-60010, proven when the Pressure Sensor was removed.

Good news!! The Pump is good and the previous Pump also may have proven to be good -- if the test had been done earlier.

Bad news!! In my opinion, there is a malfunction in the Return Valve (noting that the strainer in the Return Valve already has been cleaned).

@suprarx7nut sees it differently. He has wide experience and knowledge which I greatly respect. He is a prolific contributor to this Forum. On this issue, we have different opinions. One of the valuable things about this Forum is that there is room for different views. It is not a competition. The reader gets to choose. There is nothing to lose by following the suggestion of @suprarx7nut and continuing to apply power and trying to get fluid movement.

Some further steps which you may wish to consider:

1. Look again and more closely at the previously provided pictures and the diagram showing the cross-section of the Return Valve -- visualise what could be happening to impede flow, such as debris or sludge entering the Return Valve as AHC Fluid returns to the AHC Tank, such as during auto self-levelling, or when the vehicle is dropped N > LO or HI > N,

2. With the whole AHC Pump assembly still in place, suggest devise a method to push and pull fluid flow through the Return Valve after removing the steel pipe from the outlet in housing 48905-60010-- with the aim of shuffling the Return Valve internal mechanism backwards and forwards to dislodge any sludge or debris which may be causing interference to valve operation,

3. For example, maybe use a bicycle pump filled with AHC Fluid with suitable fittings added, or some similar arrangement, or, maybe use a compressed air nozzle, or, whatever else you can devise,

4. Question: How is it possible for debris to arrive in the Return Valve in the first place? Answer: It is possible when AHC Fluid is flowing back to the AHC Tank, carrying sludge or debris from elsewhere in the system, especially after major repairs such as those which have occurred on this vehicle,

5. Question: Maybe the strainer in the Return Valve would catch returning fluid flow and protect against sludge and debris in the return direction? Answer: No. The purpose of the Return Valve is to cause returning fluid to be diverted directly through the drillings in the housing 48905-60010 to the AHC Tank -- returning fluid DOES NOT flow backwards through the Return Valve strainer, NOR does returning fluid flow backward through the gears in AHC Pump sub-assembly,

6. For the reasons given in my Post #132, I do not consider that the pressures and flow you have described at the delivery point at housing 48905-60010 are adequate to operate the AHC functions,

7. The situation of a Return Valve fault is rare -- there is no FSM information to help, and I do not recall seeing any helpful information on this Forum,

8. I have not personally disassembled a Return Valve because the need has never arisen. If this were my vehicle, and if I were faced with the symptoms you have described, I would look for alternatives to replacing the housing 48905-60010 for USD800. [Maybe I would consider a second-hand whole Pump assembly 48910-60012 if that would yield a spare housing 48905-60010],

9. Again, if this were my vehicle, I would now try to shuffle the Return Valve internals as mentioned in para (2) above – and if that did not work, I would remove the Return Valve for careful examination, using long-nose pliers or forceps as shown in the picture at Post #132, or, first remove the strainer then in a similar way engage the Return Valve with a slightly larger wood screw, and withdraw the Return Valve from the housing 48905-60010,

10. I have a spare whole AHC Pump assembly 48910-60012 -- when time permits, I will personally explore Return Valve removal and examination,

11. I am aware of the videos at the links below -- the visuals are interesting but I have no abilities in any of the Cyrillic languages so I cannot interpret them for you. The visuals may be of some assistance in dealing with the Return Valve:

 

[suprasvobodea]

Mmmmm – best if expressions like “begs the question” and some other blue comments are put down to very understandable frustrations!!

Why is “Active Test” still appearing?? There have been multiple mentions of why that does not work when faced with DTC C1762.

You have been taken to the Return Valve in multiple Posts with diagnostic ideas and with diagrams and pictures on how to proceed over a period of almost 4 weeks – see my posts: June 13, 2024 at Post #115; June 15, 2024 in Post #121; July 4, 2024 in Post #131; July 6, 2024 in Post #132 – INCLUDING sufficient pictures on how to remove and examine the Return Valve.

On July 8, 2024 in your Post #136, you have provided a clear answer that the recommended test had been performed and which confirms high pressure and flow from the AHC Pump sub-assembly 48905-60010, proven when the Pressure Sensor was removed.

Good news!! The Pump is good and the previous Pump also may have proven to be good -- if the test had been done earlier.

Bad news!! In my opinion, there is a malfunction in the Return Valve (noting that the strainer in the Return Valve already has been cleaned).

@suprarx7nut sees it differently. He has wide experience and knowledge which I greatly respect. He is a prolific contributor to this Forum. On this issue, we have different opinions. One of the valuable things about this Forum is that there is room for different views. It is not a competition. The reader gets to choose. There is nothing to lose by following the suggestion of @suprarx7nut and continuing to apply power and trying to get fluid movement.

Some further steps which you may wish to consider:

1. Look again and more closely at the previously provided pictures and the diagram showing the cross-section of the Return Valve -- visualise what could be happening to impede flow, such as debris or sludge entering the Return Valve as AHC Fluid returns to the AHC Tank, such as during auto self-levelling, or when the vehicle is dropped N > LO or HI > N,

2. With the whole AHC Pump assembly still in place, suggest devise a method to push and pull fluid flow through the Return Valve after removing the steel pipe from the outlet in housing 48905-60010-- with the aim of shuffling the Return Valve internal mechanism backwards and forwards to dislodge any sludge or debris which may be causing interference to valve operation,

3. For example, maybe use a bicycle pump filled with AHC Fluid with suitable fittings added, or some similar arrangement, or, maybe use a compressed air nozzle, or, whatever else you can devise, (I dont have a bicycle pump and the fittings would be big problem.... But i understand and appreciate your angle. Movement in a system is alwasy good to try to backflush a system .

4. Question: How is it possible for debris to arrive in the Return Valve in the first place? Answer: It is possible when AHC Fluid is flowing back to the AHC Tank, carrying sludge or debris from elsewhere in the system, especially after major repairs such as those which have occurred on this vehicle,

5. Question: Maybe the strainer in the Return Valve would catch returning fluid flow and protect against sludge and debris in the return direction? Answer: No. The purpose of the Return Valve is to cause returning fluid to be diverted directly through the drillings in the housing 48905-60010 to the AHC Tank -- returning fluid DOES NOT flow backwards through the Return Valve strainer, NOR does returning fluid flow backward through the gears in AHC Pump sub-assembly,

6. For the reasons given in my Post #132, I do not consider that the pressures and flow you have described at the delivery point at housing 48905-60010 are adequate to operate the AHC functions,

7. The situation of a Return Valve fault is rare -- there is no FSM information to help, and I do not recall seeing any helpful information on this Forum,

8. I have not personally disassembled a Return Valve because the need has never arisen. If this were my vehicle, and if I were faced with the symptoms you have described, I would look for alternatives to replacing the housing 48905-60010 for USD800. [Maybe I would consider a second-hand whole Pump assembly 48910-60012 if that would yield a spare housing 48905-60010],

9. Again, if this were my vehicle, I would now try to shuffle the Return Valve internals as mentioned in para (2) above – and if that did not work, I would remove the Return Valve for careful examination, using long-nose pliers or forceps as shown in the picture at Post #132, or, first remove the strainer then in a similar way engage the Return Valve with a slightly larger wood screw, and withdraw the Return Valve from the housing 48905-60010,

10. I have a spare whole AHC Pump assembly 48910-60012 -- when time permits, I will personally explore Return Valve removal and examination,

11. I am aware of the videos at the links below -- the visuals are interesting but I have no abilities in any the Cyrillic languages so I cannot interpret them for you. The visuals may be of some assistance in dealing with the Return Valve:

IndoCruise -update 7/9/24

Thank you , once again for your detailed description and explanations.... they are my lifeline after 5 months of this frustration.! !

I removed the return valve based on the pictures from Russia last night and attached photos of what it looks like. I too, think something is messed up , and blocking this little valve from functioning. I think the screen in it would prevent such damage since fluid returning to the tank WILL pick up contaminants from a disturbed, open system...like mine. Now that I see how the Russians disassembled the end of it, by prying the end off with a screwdriver as a wedge, I will attempt that today. I cannot understand Russian, but I sure can follow the pictures and his hand gestures as to what to do. IF THIS DOES NOT WORK AND UPON REASSEMBLY, IT CAN NOT PRODUCE PRESSURE, THEN I WILL BE LOOKING FOR A USED PUMP FULL ASSY, & use the part 48905-60010 ($800 ) from a used full assy hole Pump assembly 48910-60012! Indocruise, I am willing to purchase one of your old pump assy, or just the return valve from a working pump, if you are willing to sell it. This is going to be a rare find unless someone from this group is reading this.

For anyone that has been reading this thread or following this adventure for the last 5 months, PLEASE LET ME KNOW IF YOU HAVE A USED Pump assembly 48910-60012 FOR SALE, I NEED IT! . Please let me know by text or call me!