AHC Damping Force Accuator Accumulator Replacement

[hkeller]

OK. Got the front to 6.9. Helped a bit. Finally check the air pressure on my new tires. It was 50 psi all around. Dialed it back 29 front and 32 rear and everthing is much better. No wonder it felt like I was riding on bricks.

 

[hkeller]

OK. GDI. After sitting overnight it now rides like it has no suspension travel at all. WTF? Others have posted with similar issues. New globes, pressure is in spec and the thing rides like a go cart. AHHH. Every small bump is felt in my teeth. Big bumps have some give. Any thoughts appreciated.

I've got some bank and might just buy a 570, but not if it will end up riding like this.

 

[PADDO]

If damping was good, it sat overnight then went bad I'm thinking maybe you have a low battery and the gen signal isn't sufficient to tell the AHC ecu it needs to turn on - maybe - or you could have a gut full of air still in the system. I'm leaning toward things that maybe temp related.
It would be good to know pressures and heights, did you reset the height sensor? Drive with Techstream on and monitor the damping steps?
Check for DTCs and do the 16 step test and lock it in position 1, softest, and go for a drive. That should tell you if it's a hydraulic/mechanical issue or electronic. The more relevant system data you can provide the better, it's easier then to eliminate what's not defective.
Did you do anything to the vehicle between when AHC/AVS was ok then not ok?

 

[hkeller]

Thanks, Paddo. I will did back into it this weekend. It does seem to ride more harshly when temps are lower. I have no DTCs. When I drive with Techstream, the steps vary from 4 to 12, best I could see while being safe. It is driving me nuts.

 

[PADDO]

FWIW my damper steps vary between 1s and 12s with the comfort switch in mid position. Might be something there? Agree it is difficult to watch the response and be safe at the same time.
It could be worth opening up and cleaning the ceramic contact tracks in your height sensors and confirming there is no corrosion and the pot wiper arms are intact as they have tiny contact fingers. Rationale here is that not only do the height sensors detect height (duh) for L, N & H they also provide the only road force feedback to the ecu by way of measuring the height differences between the UCA and chassis. There is no feedback from the accelerometers that tells the ecu the road is rough and damping needs to be adjusted accordingly - just the +/- proportional voltages from the height sensors. If they are worn (and the sliders rub constantly in a small range on the tracks) it's very conceivable that the feedback signals to the ecu could be noisy and out of range when in motion.
As a young fella maintaining naval gun and missile hydraulic servo systems if we observed $hitty dynamic responses one of the first things checked were the feedback potentiometers. That's all our height sensors are, feedback potentiometers.

 

[Falmin]

If damping was good, it sat overnight then went bad I'm thinking maybe you have a low battery and the gen signal isn't sufficient to tell the AHC ecu it needs to turn on - maybe - or you could have a gut full of air still in the system. I'm leaning toward things that maybe temp related.
It would be good to know pressures and heights, did you reset the height sensor? Drive with Techstream on and monitor the damping steps?
Check for DTCs and do the 16 step test and lock it in position 1, softest, and go for a drive. That should tell you if it's a hydraulic/mechanical issue or electronic. The more relevant system data you can provide the better, it's easier then to eliminate what's not defective.
Did you do anything to the vehicle between when AHC/AVS was ok then not ok?

I've been thinking of contacting you since I'm totally lost with my lx570 2008. The car was riding rough and bouncing when I bought it from a friend. I have replace all globes and struts, flushed and bleed the system, level the sensors etc. I'm still stuck with 1 problem that I cannot fix. When the engine is running, the car seems leveled but when it's off for couple of hours, the car leans (rear right and a bit of front right), when I start it, car levels after some seconds. It keeps happening every time I park it overnight. I did change both right sensors but didn't help. Their isn't any external leak also. I'm thinking it's an internal leak but idk what is causing it, do you have any idea? I will really appreciate it, I've already spent like 3k with different mechanics and the dealer won't spend time finding the problem but quote me to change almost everything again. Thank you for your attention.