Hoping someone can help me out with a mystery. For a while I had an intermittent left front height sensor fault. The 4x4 display would occasionally show that wheel dropped all the way down for a few minutes, then it would go back to normal. The suspension light would come on but didn't lower, except sometimes overnight. Then the car sat for a couple months until I took care of a few other things: new cooling parts, battery and alternator.
After fixing those issues and driving it again, the height sensor problem appeared again, but it also started doing the Christmas tree effect of various warning lights, and dropping to the bump stops.
So I replaced the height sensor - same problem persisted. Today I also replaced the sensor wiring pigtail, and no improvement. I've tried clearing codes and calibrating the suspension with my GAP tool, but the faults come back right away now.
The GAP tool is showing that the sensor in question's voltage is way lower than the other 3. Any ideas?
Could this be the ride level control module or a wiring fault somewhere besides the sensor pigtail?
Any clues on how to diagnose much appreciated..
By the way, I've also replaced the brake light switch since I'm getting brake switch codes too, but that had no effect.
Faults and sensor data shown below:





-----Faults------------
Engine Petrol

P0504-64 (28) Brake switch A/B correlation - Algorithm based failure - signal plausibility failure

P0504-29 (28) Brake switch A/B correlation - General signal failure - signal is invalid

HeadLight

U0400-68 (AF) Invalid data received (event diagnostic trouble code) - Algorithm based failure - event information
( on 11-11-2021 12:35:24 at 261412 km )

Instrument Pack

U0127-87 (2F) Lost communication with tire pressure monitor module - Bus signal/message failure - missing a message

Suspension

C1A72-1C (AF) Front left height sensor mechanism - General electrical failure - circuit voltage out of range
( on 11-11-2021 12:36:01 at 261412 km )

C1A03-1C (28) Front left height sensor - General electrical failure - circuit voltage out of range
( on 11-11-2021 12:37:39 at 261412 km )

Transfer Case

P1807-00 (2F) Four-wheel drive high ratio - short circuit to ground
( on 11-11-2021 12:17:42 at 261412 km )

U0132-86 (2F) Lost communication with ride level control module - Bus signal/message failure - signal is invalid
( on 11-11-2021 12:35:20 at 261412 km )

Transmission

U0416-86 (2C) Invalid data received from vehicle dynamics control module - Bus signal/message failure - signal is invalid
( on 11-11-2021 19:10:10 at 261442 km )

Vehicle Dynamic

U0421-68 (2B) Invalid data received from ride level control module - Algorithm based failure - event information
( on 11-11-2021 12:35:15 at 261412 km )

 

Seems like the TCCM transfer case control module is also a common culprit with this sort of thing. I will inspect that next, along with the ride level module and connections. The t case short circuit to ground error has been there for years, with no apparent effect.
The vehicle has had a sunroof drain issue in the past, which let moisture into the right side footwell area.
Last time I drove it I also noticed cruise control wasn't working, which is also a new thing.
hmmmm...

 

Can someone point me to the right wiring diagram in the repair manual for the height sensors? What module reports that data? The ride level/EAS module? Still looking for any tips on tracking down the issue here. Thanks!

 

Today it's not dropping the suspension down and fewer dash warning lights are lit up. Just the yellow suspension light and flashing headlight light.

 

First, look at the part number and confirm it is the right sensor for the corner you having problems with. I don't have the part numbers in front of me, but I do know they are different.
Next, make sure it is not mounted upside down.

Hope this helps.

Jeff

 

I've confirmed the part itself was fine - same result with the old part. There's a wiring or module problem somewhere. Tracing it today hopefully.

 

Here is the wiring setup...

 

Thank you. I tried to get in there today but ran out of time when I remembered I really need to take the wheel liner out to have a thorough look. Will keep you guys posted.