Backstory: A suspension fault has popped up a couple random times over the past 3 months about 10 seconds after startup. A quick ignition cycle and the compressor turns on and no warning. Nothing to worry about. I also noticed that galley pressure would slowly drop after the compressor turned off. So there’s a small leak somewhere. But only big enough to notice any drop after 2 days of sitting. Also, front right wheel makes pretty loud clunking sound on any kind of small bump now. Assumed control arm bushing is gone. I also went through the connections in the engine compartment behind the battery a few weeks back and everything was clean but I added some dielectric grease just to be safe. I e also got a locking rear diff that for the past year has been getting stuck and throwing an error message saying traction reduced.

Yesterday I parked at work and bumped the curb a bit hard with the front right wheel. Didn’t thing much of it (and could be unrelated). Left work at the end of day and the whole thing lit up with the works. Transmission fault, HDC, special programs, DSC, ABS, brake lights all on. No “F” on the cluster info center. No CEL. Suspension light pops up after about 10 seconds every time now. Suspension is locked into a height between access and standard (screen still says it’s in standard but info on cluster says suspension lowered). Compressor seems to turn on like normal.

I’ve cleared codes and there’s no momentary fix on ignition cycle. I’ve driven around 8-10 times with it like this. There are no obvious symptoms. I’ve driven as fast as 90 mph like this. Shifts great through all gears. I’ve looked through every sensor my OBD2 can read and everything looks normal including wheel speed sensors and ABS sensors on all 4 while driving, suspension height sensors on all 4.

I don’t have access to a GAP tool right now so there’s a few things I can’t test. I’m posting the list of codes below.

I’m wondering if this is an electronics/connection issue with all the control unit failures? Suspension thing? Wheel sensor thing? Rear diff thing?

Thanks for any insight!


Car Scanner ELM OBD2
DTC report
Selected brand: Land Rover
VIN: SALAA25485A308035

============1==============
P0097(00)
Raw code: 009700
ECU: 10
Status: Test not completed during this operation cycle
OBDII: Intake air temperature (IAT) sensor 2 - circuit low input; Intake Air Temperature (IAT) Sensor 2 Circuit Low Voltage

============2==============
P0098(00)
Raw code: 009800
ECU: 10
Status: Test not completed during this operation cycle
OBDII: Intake air temperature (IAT) sensor 2 - circuit high input

============3==============
U3002(62)
Raw code: F00262
ECU: 32
Status: Test not completed since last DTC clear, Test not completed during this operation cycle
OBDII: Vehicle identification number (VIN)

============4==============
C0051(64)
Raw code: 405164
ECU: 32
Status: Test not completed since last DTC clear, Test not completed during this operation cycle
OBDII: Steering Wheel Position Sensor

============5==============
C1A37(01)
Raw code: 5A3701
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============6==============
C1A35(01)
Raw code: 5A3501
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============7==============
C1A34(01)
Raw code: 5A3401
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============8==============
C1A33(01)
Raw code: 5A3301
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============9==============
C1A32(01)
Raw code: 5A3201
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============10==============
C1A31(01)
Raw code: 5A3101
ECU: 2B
Status: Test not completed since last DTC clear, Test not completed during this operation cycle

============11==============
U0416(86)
Raw code: C41686
ECU: 2B
Status: Test failed, Test failed (current drive cycle), Pending, Test failed since last DTC clear, Warning indicator requested
OBDII: Invalid data received - vehicle dynamics control module

============12==============
U1A4A(68)
Raw code: DA4A68
ECU: 20
Status: Test failed, Test failed (current drive cycle), Confirmed

============13==============
U0403(94)
Raw code: C40394
ECU: 1C
Status: Test failed, Test failed (current drive cycle), Pending, Test failed since last DTC clear
OBDII: Invalid data received - transfer box control module

============14==============
U0416(94)
Raw code: C41694
ECU: 1C
Status: Test failed, Test failed (current drive cycle), Pending, Test failed since last DTC clear
OBDII: Invalid data received - vehicle dynamics control module

============15==============
P186D(00)
Raw code: 186D00
ECU: 1A
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear

============16==============
P080A(00)
Raw code: 080A00
ECU: 1A
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear
OBDII: Clutch position not learned

 

Gallery pressure should drop.

Clunks up for can easily be control arms, but more often are the sway bar links - stupid easy to replace but best to do both at the same time since you can guide both sides up into the arms easier then fighting opposite side.

Dielectric grease goes on the connector, never the pins - just to clarify incase you did. Its a non-conductor.

What are you voltages at battery? Off and running. Sounds more like a power issue at first glance.

 

Can you clarify what you mean by galley pressure drop? Engine is running and everything is level and it’s slowly leaking out.

Also, there’s been no issues with the greased connections until now, including a 900 mile road trip. So I don’t think that suddenly failed. But I agree (hope) that it seems electric.

I’ll check the voltages off but while running it was 14V

 

Easy check for control arm bushings is to idle along at 5moh and then briskly press the brake pedal. If it knocks, it's the LCA Bushing.

How is your diff "stuck" per se?

 

The gallery it not air tight. It will leak. In fact its dumped out before the compressor fires up otherwise that quarter sized piston with that small 12v motor would not be able to fight 250psi of air. A lot of compressors actually dump "gallery" pressure so they can fire up again as needed.

Keep an eye on voltages when operating. If you have a NAV screen you can do it all the time if you enter the diagnostics area. A failing alternator can produce 14v and then suddenly brown out for a second. Also a bad battery can inhibit properly electrical flow and cause issues.

If voltages are healthy, then clear these codes and check again when it happens. If the steering sensor comes up again, then I put my money there. Your air intake temp should be looked at too, but I don't believe it would cause these issues. Just the steering sensor could.

 

I’ve never been able to recreate the knock by hitting the brakes. So should I assume sway bar? I can’t see anything wrong with either on inspection.

I get a transmission fault - traction reduced message at startup every time when it self tests

 

Trans faults can be a sign of low starting voltages, especially if you get the whole party including HDC faults. Otherwise reduced traction is because of your rear diff, which you are may be damaging by not resolving the clutch actuator issue.