TL;DR - I believe my front left suspension damper is stuck at the stiffest setting, causing bad ride quality.
This is my first post here, and I'm only posting because I think I've read every AHC thread there is. I have a 2000 LX470 with 145,000 miles, and I'm trying to troubleshoot terrible ride quality. I have the same symptoms that many others have described, I can hear and feel every tiny bump or crack in the road, even on seemingly smooth asphalt, regardless of the variable suspension switch setting. I have no complaints about the ride quality on the highway.
Most recently, I performed the 16 step damper check for the first time, and all positions EXCEPT the front left properly increased in stiffness at each step. At the start of the test, Techstream indicated that the front and rear were both at step 1, but the front left felt like it was at maximum stiffness, requiring my full body weight to cause movement, while all other corners had significant soft bounce. I pulled all AHC marked fuses, and disconnected the negative battery terminal for good measure, in an effort to clear any faults or error states that Techstream wasn't showing me. I performed the test again 2 hours later with the same results.
Here are actions I have done so far, in the order that I did them, just to provide a record of my troubleshooting process:
This is my first post here, and I'm only posting because I think I've read every AHC thread there is. I have a 2000 LX470 with 145,000 miles, and I'm trying to troubleshoot terrible ride quality. I have the same symptoms that many others have described, I can hear and feel every tiny bump or crack in the road, even on seemingly smooth asphalt, regardless of the variable suspension switch setting. I have no complaints about the ride quality on the highway.
Most recently, I performed the 16 step damper check for the first time, and all positions EXCEPT the front left properly increased in stiffness at each step. At the start of the test, Techstream indicated that the front and rear were both at step 1, but the front left felt like it was at maximum stiffness, requiring my full body weight to cause movement, while all other corners had significant soft bounce. I pulled all AHC marked fuses, and disconnected the negative battery terminal for good measure, in an effort to clear any faults or error states that Techstream wasn't showing me. I performed the test again 2 hours later with the same results.
Here are actions I have done so far, in the order that I did them, just to provide a record of my troubleshooting process:
- - Corrected high AHC pressures via torsion bar adjustment, and 30mm spacers
- - Verified proper vehicle height and cross-leveling via FSM procedures
- - New sway bar and end link bushings, front and rear
- - Fluid flush via @PADDO 's 1 can easy flush method (fluid was dark, but had minimal bubbles/frothing)
- - 16 step damper response check via FSM procedure
- - The variable suspension switch functions properly and I can feel differences at each position
- - In Techstream, with the vehicle idling on flat ground, my front and rear pressures are within FSM spec
- - Techstream shows the damper steps, front and rear, at 8 while idling on flat ground
- - I get 10 graduation marks on the AHC reservoir when going from LOW to NEUTRAL
- - Techstream shows no AHC trouble codes
- - During the 16 step damper test, all positions EXCEPT the front left properly increase in damping resistance (front left is very stiff, comparable to step 16)
- - AHC operates properly, lowering and raising the truck with no issues
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