AHC pump out? With code 1762 (1 Viewer)

[IndroCruise]

Well. Got the pumps in. And they look to be in good condition. Went to take off my whole pump and stripped the dagum feed line to the pump…soooo I said, “pump assembly is staying there for right now.”
Well I changed out the little pump with the good one the guy said there was no problems with. Nothing. Blinking off light. Tried active test. Nothing. So. Put in the second pump. Same freaking thing. Finally put back in my old pump and got it working again.

Still. Raise times are in 30 seconds.

After closer inspection you can see all three pump mechanisms have a small indentation in three completely different places. I assume this is why the pump would not work.

***Side note*** Is there anyway I can take one of the old fittings off the old pump and put it on my feed line…? And yes, I will be purchasing some flare wrenches in the future. To keep this from happening again.

View attachment 2796800

View attachment 2796801

View attachment 2796802

If not already done, suggest disassemble one of AHC Pumps -- not difficult, four Allen head bolts, but take care and lay the parts out so that they can go back together exactly as you found them. Take pictures to help. Examine the parts, especially the gears -- these do the actual pumping by catching incoming fluid which goes around the gears (not between the meshing gear teeth) and ejecting it on the discharge side. This is how very high pressures are developed. Worn or damage gears are problematic -- look for tooth wear or damage and also side wear which would increase bypass. The pump is designed to minimise this effect -- see pic and explanation far below.

Then examine both of the strainers. There are two of these things. They can be seen outlined with a bronze or brass (or similar) ring and with a good light you may be able to see the mesh inside -- which almost certainly will be a dirty black colour, not the original white. If you are handy with a pick, you may be able to prize these strainers out of the pump body -- but go gently, the mesh is very fine (fabric?) and does not like being poked with sharp implements. Alternatively, leave the strainers in place and clean by backwashing with a good clean hydrocarbon cleaning fluid, then finish with clean AHC Fluid to remove the cleaning fluid. Check that the strainers are free-flowing -- can you blow though them?

The above pic shows the pump still intact -- notice the strainer with the bronze or brass (or similar) ring

The above pic is the pump after disassembly and exposing the second strainer -- the gears are removed, showing the fluid inlet path from the strainer to the gear pump.

This is what the strainers look like (picture credit: @Zel from 200 Forum)

Ideally, when re-installing the Pump, replace the seal between the motor and the pump (Part No. 90311-10001), large O-ring (Part No. 90301-70003), the small O-ring (Part No. 90301-06012) and grommet between AHC Tank and Pump (Part No. 47255-60010) . These cost only a few dollars -- renewal is important to safeguard against air being entrained into the pump body from atmosphere and risking aeration within the pump (similar effect to cavitation). I have never found any Part Numbers for the strainers nor any other parts inside the actual Pump nor have I discovered which Toyota/Lexus supplier actually makes the AHC Pump. Instead, Toyota/Lexus intend that the whole thing be replaced -- Toyota/Lexus Part No. for the Pump is 48901-60010 -- offshore prices about USD130 from Impex, USD165 from Partsouq, plus shipping in both cases -- maybe plus USD30 (?) for delivery in USA.

Naturally, after installation and when ready to start the AHC system, ensure that the Pump is 'primed' (meaning full of fluid) using "Active Test" or direct connection to the battery for few (say 10) seconds -- otherwise the pump may refuse to start or or refuse to stay running if the pressure sensor detects no pressure or low pressure due to lack of fluid or presence of air in the pump body. Then bleed the whole system multiple times.

The diagram and explanation below is taken from the FSM:

 

[IndroCruise]

If not already done, suggest disassemble one of AHC Pumps -- not difficult, four Allen head bolts, but take care and lay the parts out so that they can go back together exactly as you found them. Take pictures to help. Examine the parts, especially the gears -- these do the actual pumping by catching incoming fluid between the meshing gear teeth and ejecting it on the discharge side. This is how very high pressures are developed. Worn or damage gears are problematic -- look for tooth wear or damage and also side wear which would increase bypass. The pump is designed to minimise this effect -- see pic and explanation far below.

View attachment 2796803

Then examine both the the strainers. There are two of these things. They can be seen outlined with a bronze or brass (or similar) ring and with a good light you may be able to see the mesh inside -- which almost certainly will be a dirty black colour, not the original white. If you are handy with a pick, you may be able to prize these strainers out of the pump body -- but go gently, the mesh is a fabric and does not like being poked with sharp implements. Alternatively, leave the strainers in place and clean by backwashing with a good clean hydrocarbon cleaning fluid, then finish with clean AHC Fluid to remove the cleaning fluid. Check that the strainers are free-flowing -- can you blow though them?

View attachment 2796807
The above pic shows the pump still intact -- notice the strainer with the bronze or brass (or similar) ring

View attachment 2796808
The above pic is the pump after disassembly and exposing the second strainer -- the gears are removed, showing the fluid inlet path from the strainer to the gear pump.

View attachment 2796814
This is what the strainers look like (picture credit: @Zel from 200 Forum)

Ideally, when re-installing the Pump, replace the seal between the motor and the pump (Part No. 90311-10001), large O-ring (Part No. 90301-70003) and small O-ring (Part No. 90301-06012). These cost only a few dollars and worth renewal to safeguard against air being entrained into the pump body from atmosphere and causing aeration with the pump (similar effect to cavitation). I have never found any Part Number for parts inside the actual Pump. The Part No. for the Pump is 48901-60010 -- about USD165 for new OEM Pump on Partsouq plus shipping.

Naturally, ensure that the Pump is primed using "Active Test" or direct connection to the battery.

The diagram and explanation below is taken from the FSM:

View attachment 2796815

Follows from the previous post -- the pic below shows the overall assembly -- note the items recommended for replacement in the FSM when replacing the pump (new or used), marked with a diamond in the right hand pic:

 

[parkeyjack]

Well. Indro. Got the new OEM pump in. Now nothing.

Blinking OFF light. Car is currently in low. Tried active test under the hood nothing. Tried active test under the dash, couldn't get this type to work. I am currently inoperable. My new OEM pump has a different little indentation than my previous (working) pump. (see above post) Replaced all seals gaskets recommended. I did replace the pump while it was in HIGH mode. Not sure if that matters? Bled the accumulator before new pump install. Powered the motor from my battery for around 5 seconds. That worked and I could here the pump motor moving. Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame because I read somewhere that worked for somebody. Has code C1762. When clearing this code using techstream, the car would lower a bit. Then I would clear it again and it would lower some more. Etc etc. I was just happy to have it "moving" haha. Code is still there.

I have not heard the actual new pump move at all since I installed. It has only went down. NEVER, UP! I think in the meantime I will just install my old pump to have it driveable.... Just really really frustrated right now.

Before install, everything was working ok. Just slow raise and lowering time, and the pump was loud.

2007 Land Cruiser

 

[parkeyjack]

Follows from the previous post -- the pic below shows the overall assembly -- note the items recommended for replacement in the FSM when replacing the pump (new or used), marked with a diamond in the right hand pic:View attachment 2796816

Well. Indro. Got the new OEM pump in. Now nothing.

Blinking OFF light. Car is currently in low. Tried active test under the hood nothing. Tried active test under the dash, couldn't get this type to work. I am currently inoperable. My new OEM pump has a different little indentation than my previous (working) pump. (see above post) Replaced all seals gaskets recommended. I did replace the pump while it was in HIGH mode. Not sure if that matters? Bled the accumulator before new pump install. Powered the motor from my battery for around 5 seconds. That worked and I could here the pump motor moving. Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame because I read somewhere that worked for somebody. Has code C1762. When clearing this code using techstream, the car would lower a bit. Then I would clear it again and it would lower some more. Etc etc. I was just happy to have it "moving" haha. Code is still there.

I have not heard the actual new pump move at all since I installed. It has only went down. NEVER, UP! I think in the meantime I will just install my old pump to have it driveable.... Just really really frustrated right now.

Before install, everything was working ok. Just slow raise and lowering time, and the pump was loud.

2007 Land Cruiser

 

[suprarx7nut]

Well. Indro. Got the new OEM pump in. Now nothing.

Blinking OFF light. Car is currently in low. Tried active test under the hood nothing. Tried active test under the dash, couldn't get this type to work. I am currently inoperable. My new OEM pump has a different little indentation than my previous (working) pump. (see above post) Replaced all seals gaskets recommended. I did replace the pump while it was in HIGH mode. Not sure if that matters? Bled the accumulator before new pump install. Powered the motor from my battery for around 5 seconds. That worked and I could here the pump motor moving. Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame because I read somewhere that worked for somebody. Has code C1762. When clearing this code using techstream, the car would lower a bit. Then I would clear it again and it would lower some more. Etc etc. I was just happy to have it "moving" haha. Code is still there.

I have not heard the actual new pump move at all since I installed. It has only went down. NEVER, UP! I think in the meantime I will just install my old pump to have it driveable.... Just really really frustrated right now.

Before install, everything was working ok. Just slow raise and lowering time, and the pump was loud.

2007 Land Cruiser

I bet it's air.

Any time you open up that pipe system, you have to get that air out. Until you do, you'll get the Abnormal Pressure code(s?) and the pump will either run very briefly or not at all. It's the system protecting itself from death or an unsafe high pressure geyser situation. Bleeding is a requirement and unfortunately, not well explained in the manual.

Tip: Try cracking loose the AHC line coming off the pump block if you've already tried bleeding the accumulator and corners. That area by the pump can trap air and is what leads to the Abnormal Pressure code. The system wants to see immediate and significant pressure increase that only liquid can provide. Air is spongy and the system can sense it. ONLY USE A LINE WRENCH. Really don't want to strip that nut. Recently worked for someone else so worth a shot to crack that loose until you get AHC fluid dripping out.

 

[parkeyjack]

I bet it's air.

Any time you open up that pipe system, you have to get that air out. Until you do, you'll get the Abnormal Pressure code(s?) and the pump will either run very briefly or not at all. It's the system protecting itself from death or an unsafe high pressure geyser situation. Bleeding is a requirement and unfortunately, not well explained in the manual.

Tip: Try cracking loose the AHC line coming off the pump block if you've already tried bleeding the accumulator and corners. That area by the pump can trap air and is what leads to the Abnormal Pressure code. The system wants to see immediate and significant pressure increase that only liquid can provide. Air is spongy and the system can sense it. ONLY USE A LINE WRENCH. Really don't want to strip that nut. Recently worked for someone else so worth a shot to crack that loose until you get AHC fluid dripping out.

I tried that as well. Might give it another shot now....Thanks for the tip. Just really weird all THREE pumps have not worked out for me but as soon as I put my old one back in...working. I will give this another shot before putting my old noisey, take forever to raise and lower pump, back in! And absolutely yes to using "flare wrenches" on this connection. I stripped my bolt but was able to get it off after ordering some of those handy wrenches.

 

[parkeyjack]

I tried that as well. Might give it another shot now....Thanks for the tip. Just really weird all THREE pumps have not worked out for me but as soon as I put my old one back in...working. I will give this another shot before putting my old noisey, take forever to raise and lower pump, back in! And absolutely yes to using "flare wrenches" on this connection. I stripped my bolt but was able to get it off after ordering some of those handy wrenches.

Well. Nope. That didn't work either. I am at a loss here.

 

[IndroCruise]

Well. Nope. That didn't work either. I am at a loss here.

Frustrations fully undertstood -- been there, done that!!

Here are a few observations and comments on the symptoms:

1. 2007 Land Cruiser 215,000 miles – previous history of slow to raise,
2. Assume that AHC pressures are known to be OK -- meaning vehicle is not overweight on AHC system, nor torsion bars out of adjustment nor rear springs weak?????
3. Vehicle now in LO, won’t lift,
4. AHC “OFF” light blinking – so ECU has turned OFF AHC system,
5. DTC C1762 – “Pump Pressure Abnormality (Pump & Motor does not supply fluid)” – this is why ECU has turned “OFF” AHC system,
6. DTC 1751 – “AHC Pump and Motor Circuit” not reported – means that C1762 occurred first, this is enough to stop the AHC Pump,
7. Original pump “slow raise and lowering time, and the pump was loud” – means either (1) air in system and aeration is occurring in AHC Pump, loss of fluid pressure is detected by Pressure Sensor, C1762 occurs, results in ECU turning pump OFF, OR, (2) blocked inlet strainer starving pump, cannot draw enough fluid, or blocked outlet strainer preventing delivery of pressure and flow, either resulting in cavitation and pressure loss -- and does not have a pump sound much different to aeration and has similar result,
8. Given latest report, it could be that the power is not arriving at the AHC system and ECU is unable to operate pump (more later about this – see para 13 below),
9. Pump can be operated from battery – indicates that AHC Pump works if directly powered – which is good, means pump motor is healthy – but does not tell what is preventing pump operation when connected in AHC system,
10. “Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame” – my guess is that you mean the Attenuator? This small device sits just below the AHC pump and is the next thing in the line from the AHC Pump. Cracking open this joint has been used by others on IH8MUD to clear air and prime pump, the same effect as cracking open the line at the AHC Pump as suggested by @suprarx7nut,
11. “Bled the accumulator before new pump install”. Not sure what this means? To bleed the Height Control Accumulator it is necessary to fill it and empty it a few times, means fill by raising LO to N, then drop to N and bleed accumulator OR use “Active Test” for this purpose. Just to be clear, there is no point trying to bleed the accumulator without doing this – Accumulator solenoid valve remains closed unless (1) the vehicle is being raised, or (2) the Accumulator is being recharged (refilled),
12. Replacement Pump was installed with vehicle at HI, so at some stage vehicle was raised, which means that ECU caused AHC Pump to at least partially fill the Accumulator – but now pump does not operate and vehicle does not raise,
13. So now vehicle will not raise AND “Active Test” not working. This a major and unusual problem -- ensure “Active Test” is performed with engine running – if “Active Test” does not work with engine running (use paperclip as connector in attached procedure to eliminate any possible Techstream errors), then suspect electrical issue, especially AHC Main Relay or AHC Fuses
14. Used AHC Pump installed from elsewhere – not clear from pics whether strainers inside either of the replacement AHC Pumps or the existing AHC Pump were checked and cleaned??? See posts #69 and #70 this thread, requires complete disassembly, observing absence of gel in outer case tells nothing about strainers,

What now???

• My first guess is persistent aeration in the pump because that is a good fit with most of the symptoms – but it is a guess. As I have no idea of the internal condition (including strainers) of any of the three used AHC pumps you have in hand, I would not eliminate possible pump problems,

• “Active Test” not working is a VERY significant issue – recommend double check “Active Test” procedure, specifically, see Page 6 of the first attachment. We now need to know whether this test works or not -- either way, that will help refine the search for the problem:
  
  1. With Ignition OFF, connect terminals Ts and E1 at DLC1 (this is the socket in the engine bay, usually over the RHS wheel arch with the word DIAGNOSTIC on the top cover. The terminal "map" is shown inside this cover. Instead of Special Service Tool (SST) 09843-18020 which is just a piece of bridging wire, find something simple -- I use an unbent paperclip for this test. Voltages are low here low, about 4.5 volts, and will not cause a problem -- but be careful to connect the correct terminals,
  2. Turn ON the engine.
  3. Push the DOWN button on the Height Select switch within 5 seconds of engine start and hold it down for 5 seconds. There will many flashing lights in the instrument cluster (because the ECU has been by-passed). Ignore these -- they will revert to normal later, after the test, when the bridge (paperclip) is removed and the AHC ON/OFF switch is pressed down for a couple of seconds,
  4. Use the combined settings to move front or rear up or down (listen for the operation of the AHC Pump and its motor)
  5. When finished, switch OFF engine, then remove the bridge (paperclip),
  6. Re-start, push down the AHC ON/OFF for a couple of seconds to clear the test.

• If “Active Test” succeeds, persist with multiple cycles of raising and lowering vehicle, focus on bleeding the Height Control Accumulator, and when clear, re-bleed each ‘globe’. As mentioned by @suprarx7nut, this cannot be rushed, takes time and patience. I know how mad it can be – I still have a problem vehicle on this side of the world awaiting my further attention.

• If “Active Test” cannot be made to work, then the cause of that problem has to be found. It is very late on this side of the world – I will think about it further but I need to take a break and take the risk of giving you even more posts anf information to read – this will give you an idea where to look for the AHC Main Relay and the AHC-B fuse if it comes to that:
• Quick question about AHC ride with extra weight - https://forum.ih8mud.com/threads/quick-question-about-ahc-ride-with-extra-weight.1247828/page-4#post-13959941

 

[parkeyjack]

Well. Nope. That didn't work either. I am at a loss here.

Put my old pump in and it started right up.... The only thing I can think of is the indentation on the back. It was different than my old pump. See picture. I mean this is ridiculous.

 

[parkeyjack]

Frustrations fully undertstood -- been there, done that!!

Here are a few observations and comments on the symptoms:

1. 2007 Land Cruiser 215,000 miles – previous history of slow to raise,
2. Assume that AHC pressures are known to be OK -- meaning vehicle is not overweight on AHC system, nor torsion bars out of adjustment nor rear springs weak?????
3. Vehicle now in LO, won’t lift,
4. AHC “OFF” light blinking – so ECU has turned OFF AHC system,
5. DTC C1762 – “Pump Pressure Abnormality (Pump & Motor does not supply fluid)” – this is why ECU has turned “OFF” AHC system,
6. DTC 1751 – “AHC Pump and Motor Circuit” not reported – means that C1762 occurred first, this is enough to stop the AHC Pump,
7. Original pump “slow raise and lowering time, and the pump was loud” – means either (1) air in system and aeration is occurring in AHC Pump, loss of fluid pressure is detected by Pressure Sensor, C1762 occurs, results in ECU turning pump OFF, OR, (2) blocked inlet strainer starving pump, cannot draw enough fluid, or blocked outlet strainer preventing delivery of pressure and flow, either resulting in cavitation and pressure loss -- and does not have a pump sound much different to aeration and has similar result,
8. Given latest report, it could be that the power is not arriving at the AHC system and ECU is unable to operate pump (more later about this – see para 13 below),
9. Pump can be operated from battery – indicates that AHC Pump works if directly powered – which is good, means pump motor is healthy – but does not tell what is preventing pump operation when connected in AHC system,
10. “Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame” – my guess is that you mean the Attenuator? This small device sits just below the AHC pump and is the next thing in the line from the AHC Pump. Cracking open this joint has been used by others on IH8MUD to clear air and prime pump, the same effect as cracking open the line at the AHC Pump as suggested by @suprarx7nut,
11. “Bled the accumulator before new pump install”. Not sure what this means? To bleed the Height Control Accumulator it is necessary to fill it and empty it a few times, means fill by raising LO to N, then drop to N and bleed accumulator OR use “Active Test” for this purpose. Just to be clear, there is no point trying to bleed the accumulator without doing this – Accumulator solenoid valve remains closed unless (1) the vehicle is being raised, or (2) the Accumulator is being recharged (refilled),
12. Replacement Pump was installed with vehicle at HI, so at some stage vehicle was raised, which means that ECU caused AHC Pump to at least partially fill the Accumulator – but now pump does not operate and vehicle does not raise,
13. So now vehicle will not raise AND “Active Test” not working. This a major and unusual problem -- ensure “Active Test” is performed with engine running – if “Active Test” does not work with engine running (use paperclip as connector in attached procedure to eliminate any possible Techstream errors), then suspect electrical issue, especially AHC Main Relay or AHC Fuses
14. Used AHC Pump installed from elsewhere – not clear from pics whether strainers inside either of the replacement AHC Pumps or the existing AHC Pump were checked and cleaned??? See posts #69 and #70 this thread, requires complete disassembly, observing absence of gel in outer case tells nothing about strainers,

What now???

• My first guess is persistent aeration in the pump because that is a good fit with most of the symptoms – but it is a guess. As I have no idea of the internal condition (including strainers) of any of the three used AHC pumps you have in hand, I would not eliminate possible pump problems,

• “Active Test” not working is a VERY significant issue – recommend double check “Active Test” procedure, specifically, see Page 6 of the first attachment. We now need to know whether this test works or not -- either way, that will help refine the search for the problem:
  
  1. With Ignition OFF, connect terminals Ts and E1 at DLC1 (this is the socket in the engine bay, usually over the RHS wheel arch with the word DIAGNOSTIC on the top cover. The terminal "map" is shown inside this cover. Instead of Special Service Tool (SST) 09843-18020 which is just a piece of bridging wire, find something simple -- I use an unbent paperclip for this test. Voltages are low here low, about 4.5 volts, and will not cause a problem -- but be careful to connect the correct terminals,
  2. Turn ON the engine.
  3. Push the DOWN button on the Height Select switch within 5 seconds of engine start and hold it down for 5 seconds. There will many flashing lights in the instrument cluster (because the ECU has been by-passed). Ignore these -- they will revert to normal later, after the test, when the bridge (paperclip) is removed and the AHC ON/OFF switch is pressed down for a couple of seconds,
  4. Use the combined settings to move front or rear up or down (listen for the operation of the AHC Pump and its motor)
  5. When finished, switch OFF engine, then remove the bridge (paperclip),
  6. Re-start, push down the AHC ON/OFF for a couple of seconds to clear the test.

View attachment 2809558

• If “Active Test” succeeds, persist with multiple cycles of raising and lowering vehicle, focus on bleeding the Height Control Accumulator, and when clear, re-bleed each ‘globe’. As mentioned by @suprarx7nut, this cannot be rushed, takes time and patience. I know how mad it can be – I still have a problem vehicle on this side of the world awaiting my further attention.

• If “Active Test” cannot be made to work, then the cause of that problem has to be found. It is very late on this side of the world – I will think about it further but I need to take a break and take the risk of giving you even more posts anf information to read – this will give you an idea where to look for the AHC Main Relay and the AHC-B fuse if it comes to that:
• Quick question about AHC ride with extra weight - https://forum.ih8mud.com/threads/quick-question-about-ahc-ride-with-extra-weight.1247828/page-4#post-13959941

All good info here. Yes I am sure that I can get active test to work. It just does absolutely nothing. Can't hear the pump activate at all. Rapid blinking off light. I have my old pump currently in now and everything is back to working normally, albeit very noisy and slow raise and lower times, but i can live with it. Then hello IRONMAN! Seriously, life is too short to be dealing with AHC problems. I was camp AHC, but this has been the final straw for me, I do believe. Thanks for all the help you guys are great!

 

[IndroCruise]

Put my old pump in and it started right up.... The only thing I can think of is the indentation on the back. It was different than my old pump. See picture. I mean this is ridiculous.

View attachment 2809588

Mmmmmmmmmmmmmmmm -- more thought required. We are missing something!! Did not realise that at a new OEM Pump also failed to start -- should be reasonable to assume that a new AHC Pump is in good order. Now wondering whether there are slightly different pump models eg new or older LC100/LX470 or LX570 etc ....

 

[parkeyjack]

Frustrations fully undertstood -- been there, done that!!

Here are a few observations and comments on the symptoms:

1. 2007 Land Cruiser 215,000 miles – previous history of slow to raise,
2. Assume that AHC pressures are known to be OK -- meaning vehicle is not overweight on AHC system, nor torsion bars out of adjustment nor rear springs weak?????
3. Vehicle now in LO, won’t lift,
4. AHC “OFF” light blinking – so ECU has turned OFF AHC system,
5. DTC C1762 – “Pump Pressure Abnormality (Pump & Motor does not supply fluid)” – this is why ECU has turned “OFF” AHC system,
6. DTC 1751 – “AHC Pump and Motor Circuit” not reported – means that C1762 occurred first, this is enough to stop the AHC Pump,
7. Original pump “slow raise and lowering time, and the pump was loud” – means either (1) air in system and aeration is occurring in AHC Pump, loss of fluid pressure is detected by Pressure Sensor, C1762 occurs, results in ECU turning pump OFF, OR, (2) blocked inlet strainer starving pump, cannot draw enough fluid, or blocked outlet strainer preventing delivery of pressure and flow, either resulting in cavitation and pressure loss -- and does not have a pump sound much different to aeration and has similar result,
8. Given latest report, it could be that the power is not arriving at the AHC system and ECU is unable to operate pump (more later about this – see para 13 below),
9. Pump can be operated from battery – indicates that AHC Pump works if directly powered – which is good, means pump motor is healthy – but does not tell what is preventing pump operation when connected in AHC system,
10. “Cracked the HIGH PRESSURE little bottle underneath AHC pump on frame” – my guess is that you mean the Attenuator? This small device sits just below the AHC pump and is the next thing in the line from the AHC Pump. Cracking open this joint has been used by others on IH8MUD to clear air and prime pump, the same effect as cracking open the line at the AHC Pump as suggested by @suprarx7nut,
11. “Bled the accumulator before new pump install”. Not sure what this means? To bleed the Height Control Accumulator it is necessary to fill it and empty it a few times, means fill by raising LO to N, then drop to N and bleed accumulator OR use “Active Test” for this purpose. Just to be clear, there is no point trying to bleed the accumulator without doing this – Accumulator solenoid valve remains closed unless (1) the vehicle is being raised, or (2) the Accumulator is being recharged (refilled),
12. Replacement Pump was installed with vehicle at HI, so at some stage vehicle was raised, which means that ECU caused AHC Pump to at least partially fill the Accumulator – but now pump does not operate and vehicle does not raise,
13. So now vehicle will not raise AND “Active Test” not working. This a major and unusual problem -- ensure “Active Test” is performed with engine running – if “Active Test” does not work with engine running (use paperclip as connector in attached procedure to eliminate any possible Techstream errors), then suspect electrical issue, especially AHC Main Relay or AHC Fuses
14. Used AHC Pump installed from elsewhere – not clear from pics whether strainers inside either of the replacement AHC Pumps or the existing AHC Pump were checked and cleaned??? See posts #69 and #70 this thread, requires complete disassembly, observing absence of gel in outer case tells nothing about strainers,

What now???

• My first guess is persistent aeration in the pump because that is a good fit with most of the symptoms – but it is a guess. As I have no idea of the internal condition (including strainers) of any of the three used AHC pumps you have in hand, I would not eliminate possible pump problems,

• “Active Test” not working is a VERY significant issue – recommend double check “Active Test” procedure, specifically, see Page 6 of the first attachment. We now need to know whether this test works or not -- either way, that will help refine the search for the problem:
  
  1. With Ignition OFF, connect terminals Ts and E1 at DLC1 (this is the socket in the engine bay, usually over the RHS wheel arch with the word DIAGNOSTIC on the top cover. The terminal "map" is shown inside this cover. Instead of Special Service Tool (SST) 09843-18020 which is just a piece of bridging wire, find something simple -- I use an unbent paperclip for this test. Voltages are low here low, about 4.5 volts, and will not cause a problem -- but be careful to connect the correct terminals,
  2. Turn ON the engine.
  3. Push the DOWN button on the Height Select switch within 5 seconds of engine start and hold it down for 5 seconds. There will many flashing lights in the instrument cluster (because the ECU has been by-passed). Ignore these -- they will revert to normal later, after the test, when the bridge (paperclip) is removed and the AHC ON/OFF switch is pressed down for a couple of seconds,
  4. Use the combined settings to move front or rear up or down (listen for the operation of the AHC Pump and its motor)
  5. When finished, switch OFF engine, then remove the bridge (paperclip),
  6. Re-start, push down the AHC ON/OFF for a couple of seconds to clear the test.

View attachment 2809558

• If “Active Test” succeeds, persist with multiple cycles of raising and lowering vehicle, focus on bleeding the Height Control Accumulator, and when clear, re-bleed each ‘globe’. As mentioned by @suprarx7nut, this cannot be rushed, takes time and patience. I know how mad it can be – I still have a problem vehicle on this side of the world awaiting my further attention.

• If “Active Test” cannot be made to work, then the cause of that problem has to be found. It is very late on this side of the world – I will think about it further but I need to take a break and take the risk of giving you even more posts anf information to read – this will give you an idea where to look for the AHC Main Relay and the AHC-B fuse if it comes to that:
• Quick question about AHC ride with extra weight - https://forum.ih8mud.com/threads/quick-question-about-ahc-ride-with-extra-weight.1247828/page-4#post-13959941

To be clear. Yes 2007 Land Cruiser with 182,000 miles. New globes. King Springs in the rear. All pressures were within spec. Rear was a bit low due to having King Springs with no added weight. Did a mild mild sensor lift (Not fully maxed out, or nowhere near it). Nothing out of the norm for AHC though...

 

[parkeyjack]

Mmmmmmmmmmmmmmmm -- more thought required. We are missing something!! Did not realise that at a new OEM Pump also failed to start -- should be reasonable to assume that a new AHC Pump is in good order. Now wondering whether there are slightly different pump models eg new or older LC100/LX470 or LX570 etc ....

Yes. It is weird. Really really weird. That indentation is the only thing I see that is different on the pumps...

 

[suprarx7nut]

Yes. It is weird. Really really weird. That indentation is the only thing I see that is different on the pumps..

Very strange. Wish I could see this one first hand.

When you say cracking the line didn't work, did you get fluid immediately? Or was there a sense that some air escaped? Have you seen any air during bleeding?

Is the 1762 code the only one that appears?

How slow is your raise/lower in seconds?

 

[parkeyjack]

Very strange. Wish I could see this one first hand.

When you say cracking the line didn't work, did you get fluid immediately? Or was there a sense that some air escaped? Have you seen any air during bleeding?

Is the 1762 code the only one that appears?

How slow is your raise/lower in seconds?

Yeah. Wish someone was here to witness this! Got fluid pretty quickly did not feel or hear any air escaping. I had a bit of air come out of the accumulator when I bled. Just bled the system like 3 times. 4 on the accumulator. Yes. That was the only code.

Lower from N to L 15 seconds
Raise from L to N 35 seconds sometimes longer sometimes shorter.
Raise from N to H 15 seconds
Lower from H to N 8 seconds

I know from the factory should raise in 15 seconds and drop in 8. So I was just trying to rememdy that. I am very OCD. So if I know something is not working perfectly.... I try to fix. It is good enough for what it is right now. Unfortunately there is not a whole lot of info on the system out there and I do not feel like going on a goose chase to figure out why my new OEM pump is not working. I think I am done with AHC. No offense. It is a great system. Just gets a bit complicated once something goes wrong, or in my case, doesn't go right.

 

[suprarx7nut]

Yeah. Wish someone was here to witness this! Got fluid pretty quickly did not feel or hear any air escaping. I had a bit of air come out of the accumulator when I bled. Just bled the system like 3 times. 4 on the accumulator. Yes. That was the only code.

Lower from N to L 15 seconds
Raise from L to N 35 seconds sometimes longer sometimes shorter.
Raise from N to H 15 seconds
Lower from H to N 8 seconds

I know from the factory should raise in 15 seconds and drop in 8. So I was just trying to rememdy that. I am very OCD. So if I know something is not working perfectly.... I try to fix. It is good enough for what it is right now. Unfortunately there is not a whole lot of info on the system out there and I do not feel like going on a goose chase to figure out why my new OEM pump is not working. I think I am done with AHC. No offense. It is a great system. Just gets a bit complicated once something goes wrong, or in my case, doesn't go right.

I'm thinking those slow raise times are an accumulator fault, not the pump.

The accumulator speeds up raise times - it's only purpose in life. The pump finishes off the raise to dial it in, but it's the accumulator that does the heavy lifting. If the pump is failing, you should get other problems (failure to maintain ride heights, failure to charge accumulator, code 1762, etc...).

When you bled the accumulator, was it 100% perfect fluid on the last bleed? Air in the accumulator bleed process can indicate a dying membrane in the accumulator - which would yield a loud pump and slow raise times.

And then I'm thinking the pump failures are a failure to prime. Common and annoying after pump changes or running a pump dry during a bleed. Often stumps dealers and DIY mechanics alike.

Sorry to hear about the frustration. Can't blame you for getting beaten down by multiple failed attempts. Appreciate any further insight you can provide. This info helps quite a bit!

 

[parkeyjack]

I'm thinking those slow raise times are an accumulator fault, not the pump.

The accumulator speeds up raise times - it's only purpose in life. The pump finishes off the raise to dial it in, but it's the accumulator that does the heavy lifting. If the pump is failing, you should get other problems (failure to maintain ride heights, failure to charge accumulator, code 1762, etc...).

When you bled the accumulator, was it 100% perfect fluid on the last bleed? Air in the accumulator bleed process can indicate a dying membrane in the accumulator - which would yield a loud pump and slow raise times.

And then I'm thinking the pump failures are a failure to prime. Common and annoying after pump changes or running a pump dry during a bleed. Often stumps dealers and DIY mechanics alike.

Sorry to hear about the frustration. Can't blame you for getting beaten down by multiple failed attempts. Appreciate any further insight you can provide. This info helps quite a bit!

Could be accumulator.
Never had a problem with maintaining ride heights. Only got the 1762 code after installing new pumps.

Yes. It was perfect fluid. I have not ran techstream again to see where my accumulator pressures are at but if I remember correctly they were in the safe zone... Honestly just tired at this point, and happy to have a functioning suspension.

The pump is quite noisy as well. I was helping a buddy out with his 06 LC similar miles as mine. Same color. Ha! Anyways his pump was quiet as a mouse which made me think it was my pump. My pump will continue to run for around 20 seconds after the height is dialed in and light has stopped flashing. Hopefully this might help someone down the road. I know I have searched and read up on just about every thread that has these similar issues.

 

[suprarx7nut]

Could be accumulator.
Never had a problem with maintaining ride heights. Only got the 1762 code after installing new pumps.

Yes. It was perfect fluid. I have not ran techstream again to see where my accumulator pressures are at but if I remember correctly they were in the safe zone... Honestly just tired at this point, and happy to have a functioning suspension.

The pump is quite noisy as well. I was helping a buddy out with his 06 LC similar miles as mine. Same color. Ha! Anyways his pump was quiet as a mouse which made me think it was my pump. My pump will continue to run for around 20 seconds after the height is dialed in and light has stopped flashing. Hopefully this might help someone down the road. I know I have searched and read up on just about every thread that has these similar issues.

That's good, that's how it should work. That pump run time after solid light is the height accumulator charging up for the next raise in the future.

Loud pump is always entrained air from what I've seen/read. Annoyingly a failing gas chamber or height accumulator will constantly produce new gas into the system until it's replaced and by the time most folks get around to addressing it, the gas is just everywhere. Needs a lot of bleeding to correct.

Anyways, thanks for the follow ups and pump pics. Unfortunate you weren't able to conquer the loud pump, but glad the system is working again.

 

[Moridinbg]

I got C1751 & C1762 as well

I was adjusting pressures and ride heights after all the crap that I have recently put on my Cruiser. I moved it N<>L maybe 20 times within a couple of hours, checking pressures and resetting ride height. Didn't go to H at all. As I was adjusting sensors rise time was very high at one point - two times slower than usual, but after that it went back to normal.
When I was almost ready it gave me the error codes once, but I hadn't tightened the rear sensor arm and it was sliding in the slot while rising. Fixed that, cleared DTCs, then had to park the car for 30 minutes to run some errands.
After that I lowered it one last time and after I tried to rise it back to N it didn't bulge. No noises or anything. Half a minute later OFF started blinking... The motor & pump assembly was very warm/hot.

Then I fried my Techstream cable Turns out that if I connect the cable to my laptop and connect the laptop to a 90W PD USB-C car charger it fries the cable. The LED does not light up any more and no device appears in Device Manager. Linux doesn't see anything with lsusb either, so it's 100% dead.
I am pretty sure it's the charging because it's the second cable I fried this way... The first one was a few years old and has been tossed around a lot, so I thought that it just died, but it too was right after I connected the laptop to the charger, so now I am sure.. I am urgently getting an overpriced cable from a local seller tomorrow.

Anyway, I think that the 20 rises and lowers took their toll. Haven't hit the motor with a hammer yet or connected it directly to 12V and just read about the DLC1, so will be trying that tomorrow. For now I suspect that the motor gave up.

 

[Moridinbg]

My motor is dead. It measures short circuit between the terminals. So apparently it can burn out from overuse without any failsafe kicking in and more importantly, without the fuse burning! I will be trying out an entire assembly with the motor, pump, reservoir, etc, removed from another car tomorrow and might try to have my motor rewound as a spare.