RESOLVED - Air Suspension Fault After De-Pressurize - BIG GNARLY LEAK!

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txfromwi

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2013 & 2015 Houston TX. 2016 Rochester NY
LR4 60K Miles 2016

Making short a long story...

IID Tool for all changes
Replaced the air suspension compressor - AMK for AMK and AMK software running - everything came back to life just fine - drove it around a bit - everything fine.

More work...
Up on jack stands - all 4 wheels.
Re-did the air compressor to fix a fitment issue with the shroud - total removal and re-install.
Did the brakes.
Replaced front lower control arms.
Take off the jack stands

Try to re-enable suspension
Back end comes up OK
Front end will not come up.

Back on 4 jack stands - maybe the sensors are outside calibration range
Same

Off of jack stands
Rear valve test - fine up/down no problems
Front valve test - nope - no response, just sits there

Pump is running, sounds good, I don't hear any leaks, but then again it's noisy..
Vehicle gives generic Suspension Fault
IID:
C1131-92 (2E) Air Supply Component Failure
C1A20-64 (AE) Pressure Increases too Slowly, Algorithm Based Failure, Signal Plausibility Failure

Current Height
The 2013 for reference F 32.5", R 33.5"
The 2016 now F 30.0", R 32.75"

IID Tools Says
Current Height
-60 -55
-18 -14

Voltage at Valves
1.4 3.5
3.4 1.8

I can control with the IID for the time before the vehicle throws the Suspension Fault idiot light.
During that time I can watch the cross link valves and the individual valves.
I can raise and lower the back end, I can see both individual back end valves go to 100%, but the cross rear link valve stays at 0.
On the front end, the individual valves and the cross link valves all stay at 0.
I can also see the Gallery Pressure move from a resting pressure of 99kPa to 700 kPa and the Reservoir valve at 100 when the pump is running
When the idiot light triggers, the pump shuts down, the reservoir valve goes to 0 and the gallery pressure bleeds down to 99kPa
From mechanics manual, gallery pressure must be at the common line that connects the pump to all 4 individual corner valves.

Seems to me to be the control for the individual front corner valves - is there an inhibit somewhere? Mechanics manual also says that there is an interface to the brakes ABS system. I did the brakes, but just pads and rotors - but this time the system was depressurized when I did the brakes - did something strange happen??

Thoughts?

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Last edited:

Mith_21

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bro can you help me out i got the same codes but small changes do u know how to change it... c1131-92 (68).
 

Tapps33

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Based off the iiD tool's solenoid values, it seems to me the front valve block may be bad. If the system is commanding it to actuate and it's not "actuating" that's why the values stay at 0. Internal short maybe? Dumb question, but have you checked all the fuses to make sure there's power to the valve block? I believe they're # 3P and 35E. It could be when you were changing the brakes somehow you pinched/nicked a wire....or maybe damaged the ground for the that particular valve block? I believe it's right there inside the wheel well, but don't quote me on that. If you have a multimeter, try seeing if you get any voltage when trying to move the suspension.....although that may be a 2 person job, and you may need to come from behind the connector to leave it connected or the system may yell at you.

Also, per the mechanics manual, the crosslink solenoid only actuates when the vehicle is actually driving at slow speeds to assist with low speed handling. It doesn't really do anything during height adjustments. Which would explain why the front and rear are always at 0....I bet if you monitored your values and drove the car around the block you'd see it move off 0.

The other possibility is that your compressor is just running too slow and can't build enough pressure fast enough, so the system isn't triggering the front valves....although the iiD tool should bypass all of that and just actuate them.
 

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