AHC Flush failure (1 Viewer)

[llaga]

My 2008 LX570 with 133,000miles,

About the last 5K miles or so miles I noticed the ride was getting stiff feel and hard, I wanted to try flush before buying globes.

I decided to do AHC flush that failed.

After doing a standard flush the car is now a bump stops and will not go up.

I then bleed the Suspension Control Pump Accumulator after this I was able to get the car to Normal, but when I went to Low and tried to go back up It would not. I have the Check 4-WHEEL AHC Systems, the dash show Low but not highlighted.

I hooked up Techstream and cleared the error C1763 Abnormal oil pressure for Pump Motor but it comes back on within 20sec. or less.

Today we removed the pump assy. hooked a 12V battery and applied power for about .5 sec but nothing came out of the inlet just dripping. I took AHC oil and a hand pump and pump oil back through the inlet to prime pump, I installed a 5K psi gauge on pump I applied power for just about .5sec, gauge shot up to 400psi, I did that again for about 1sec and gauge when to over 1500psi, pump seems to be good if I have a good prime.

We installed the pump assy. started the car but car would not come up, I could hear the pump but would turn off after a few secs., with Techstream running and turning the car off and on about 10 times and the pressure in Techstream would show up to 2.7Mpa but car would still not move, after this the pressure would not do anything but 0.16 Mpa and the 4-Wheel AHC error come on within a few seconds of starting car.

Is there a way to in Techstream to force pump to run to build pressure, even if 4-Wheel AHC error is on? I see on forums there is a way but I down see the menu item that they list.

If I go to Active Test I see several options, see pictures.

I will try this tomorrow: The line from pump goes to the Height Control Valve first then a line from there Height Control Valve goes to Suspension Control Pump Accumulator,(looking at a diagram) I’m going to remove the line from Height Control Valve and prime that line to pump.

If you anyone knows of something else I should do please let me know. I’m at my wits’ end



Thanks,
Lance

 

[radman]

nice work on the troubleshooting so far!

have you seen this thread?

AHC Problems immediately after Dealer Flush

I’m curious. Why not just suck the fluid out of the reservoir and swap with clean fluid? I know its a shortcut, but if it remove 90% of the old fluid, wouldn’t that be good? I know this doesn’t help op, but I’m thinking of servicing mine at 75k. OP, is Lexus going to cover the pump? The...

forum.ih8mud.com

 

[grinchy]

interesting how his has happened once before in three years and now 3x in same week. Crazy.

good troubleshooting so far!

agree that getting fluid in the reservoir and in the line directly after the pump is key.

i‘m guessing since you’re in L mode there is no longer pressure In the system?

just curious if you know how air entered the system to begin with?

we want to get you whole but also learn what to avoid for others flushing for maintenance.

 

[grinchy]

Of the tests pictured accumulator valve looks like worth a try

 

[llaga]

interesting how his has happened once before in three years and now 3x in same week. Crazy.

good troubleshooting so far!

agree that getting fluid in the reservoir and in the line directly after the pump is key.

i‘m guessing since you’re in L mode there is no longer pressure In the system?

just curious if you know how air entered the system to begin with?

we want to get you hole but also learn what to avoid for others flushing for maintenance.

Yes I agree about being in L mode having no pressure I bleed the Suspension Control Pump Accumulator again and it had no pressure when I cracked the bleeder.

I don't know how air got in or even if it did until we removed pump. That's what I'm concerned about also, I was very careful not to let reservoir get low.


Thanks,
Lance

 

[llaga]

Of the tests pictured accumulator valve looks like worth a try

OK I will give that a try.

Thanks,
Lance

 

[grinchy]

Mercedes abc system which is similar says to

If in fact the pump was run dry, the pump may require priming to get operational again. This is done by pressurizing the reservoir to help the pump get the fluid moving again.

to help prime pump

citation ABC System - http://mercedes-abc-drive-carefully.blogspot.com/2014/08/overview-abc-system-isthe-key-part-of.html

 

[grinchy]

Unfortunately I can’t recall any forum members doing an at home prime, but I’m confident we can figure it out

 

[llaga]

Mercedes abc system which is similar says to

If in fact the pump was run dry, the pump may require priming to get operational again. This is done by pressurizing the reservoir to help the pump get the fluid moving again.

to help prime pump

citation ABC System - http://mercedes-abc-drive-carefully.blogspot.com/2014/08/overview-abc-system-isthe-key-part-of.html

I will try that too, that's good Idea.

Thanks,
Lance

 

[grinchy]

How to prime the abc pump at 22:35 or so

 

[grinchy]

On reread I see you have the pump primed. Sorry about that. Good job!

you’re clearing the dtc with tech stream?

and pressure got rebuilt for A bit. Interesting.

but Now no pressure. I think it must have lost prime, but I’m just guessing.

 

[NYC570]

When a rusted line failed on my LX, a lot of fluid spilled, the truck dropped and I got the error code. I limped home and checked the fluid level in the reservoir and it was completely dry. I'm not sure whether the pump ran dry but this is most likely the case since the reservoir was dry and it threw the error.

To prevent the pump from working while moving the truck to replace the line (I had to move it a few times), I removed the AHC fuse in the engine compartment. I belive it's number 18. Once I replaced the line, I filled up the reservoir. I put in the the fuse back in and started the truck. To my surprise I didn't have to use techstream to clear the code or prime the pump. The pump started working and the truck raised. I then proceeded to bleed the system at the four corners a few times and then at the center unit. When bleeding the center unit, fluid eventually stopped coming out. In not sure whether this is supposed to happen but the system has been working fine since.

I'm not sure what the trick is to get the pump working again. Perhaps it's pressing the button to raise it after turning it on or removing and putting the fuse back on, but as I mentioned, I didn't even have to use techstream to clear the code.

 

[nwfl4runner]

With techstream, clear the DTC of abnormal pressure, then go to active test and try to raise one of the front wheels. Does anything happen?

 

[llaga]

With techstream, clear the DTC of abnormal pressure, then go to active test and try to raise one of the front wheels. Does anything happen?

I have tried this but before I can get back to active test the abnormal pressure alarms comes back on. We are going to remove the pump line tomorrow and make sure it clean and prime from the line also.

 

[nwfl4runner]

I have tried this but before I can get back to active test the abnormal pressure alarms comes back on. We are going to remove the pump line tomorrow and make sure it clean and prime from the line also.

i had the same error when I replaced the rear shocks. Takes a few times but eventually the error stayed off and it filled

edit: Not implying they're the same error, but I had many of the same symptoms before I went through techstream of clearing the code multiple times.

 

[llaga]

Mercedes abc system which is similar says to

If in fact the pump was run dry, the pump may require priming to get operational again. This is done by pressurizing the reservoir to help the pump get the fluid moving again.

to help prime pump

citation ABC System - http://mercedes-abc-drive-carefully.blogspot.com/2014/08/overview-abc-system-isthe-key-part-of.html

Today we took the small vent tube on the cap reservoir and put just a little air pressure in the reservoir, started car, car raised to Normal mode, then from Normal mode to High and we had to give the reservoir another blast and car raise.

It's seem the pump will not stay primed, we add a shot of air and set the car Normal mode, bleed all 4 corners.

Started the car again but would not lift without a shot of air.

We got carried away and shot to much air the reservoir busted and oil poured everywhere.

I took the pump assy. out of car removed the pump from pump motor, turn the pump when off motor it's not lockup or hard to turn. I cleaned it real good.

I JB welded the reservoir and letting it cure till tomorrow and try it one more time, before I order a Pump Assy.

At this time it's seems to be a pump issue, pump not keeping prime for some reason it seems.

If anybody has any ideas please let me know.


Thanks,
Lance

 

[grinchy]

Thanks for the update. Did you also bleed the accumulator (fifth) that is the first stopping point after the reservoir? After you get up to normal bleed that one first.

 

[llaga]

Thanks for the update. Did you also bleed the accumulator (fifth) that is the first stopping point after the reservoir? After you get up to normal bleed that one first.

We did but after the reservoir busted, so we will give it a try tomorrow when the JB weld cures.

Thanks,
Lance

 

[crow1969]

We did but after the reservoir busted, so we will give it a try tomorrow when the JB weld cures.

Thanks,
Lance

Any progress here? Mines been sitting on the bump stops with the same issue for a week.

 

[llaga]

Any progress here? Mines been sitting on the bump stops with the same issue for a week.

Yes we got it going, it's been working well for 2 days.

I removed the AHC pump motor assy. removed pump off the motor, and disassembled the pump removed rubber o-rings and sprayed and cleaned in carburetor cleaner.
Didn't see anything clogged.

Soaked pump in AHC fluid and rotated, left in AHC fluid overnight.

Tested pump and primed, plugged outlet hole and replaced assy. back.

Started LX and everything started working.