Hi All

I've had an intermittent suspension issue for a while. Sometimes it works, raises, lowers and adjusts when needed, and other times seem to get a common problem that after 30s on start up, it throws an error message. IID shows the following errors:

C1131-92 (2C) Air supply - Component failure - performance or incorrect operation.
C1A20-64 (AF) - Pressure increases too slow when filling reservoir - Algorithm based failure - signal plausibility failure.

I had the compressor and front and rear valve block replaced 2 years ago and it's worked fine. Chancing my luck, I replaced the front valve block and still have the same issue. Took the replaced valve block apart to inspect and all looks fine.

When driving, the car with drop the front to the bump stops and cause a red warning message. If I recalibrate the ride height using the gap tool, after several attempts the suspension will raise fine, sometimes with the "slow raise" warning on the dash.

The back doesn't drop at all.

I guess I need to test the air bags for leaks but I can't get them to extend to see if this is the route cause.

Anyone have any other ideas for me to try?

Thanks

 

Quick update, I re-flashed the ECU for the compressor and managed to get the vehicle to raise on all four corners. Compressor was topping out at 247F but I had deflated the system and it's about 100F + humidity here today.

I've pulled the fuse to see if the corner drops overnight.

However, off road height is sitting a little lower than normal ride height, and I can't calibrate up from there using the IID... *Strokes chin...*

 

Those codes point to a failed compressor...

 

Thanks for the reply.

Hoping it's not the compressor as that was only replaced 2 years ago to the AMK compressor. 2 year shelf life or just unlucky? Given the back rises normally I was hoping it's not the case. After pulling the fuse, the front or rear hasn't dropped overnight, so will be interesting to see if it has another 12 hours later.

I just recalled that occasionally I would get a warning saying it's in extended mode, when it wasn't and to reset when clear of obstacle. I've taken a punt and ordered some ride height sensors for the front as they are pretty grubby and are probably close to the end, if not at it.

If it is the compressor... Pah.

 

Ok - Good news. 5 days in and the suspension hasn’t dropped so I can rule out a leak.

Replaced the front height sensors and tried calibrating but the front won’t lift.

When I start up and immediately put it into off road access the back raises immediately. Warning message suspension raising slowly and then error message, with the occasional extended mode warning message to boot. Front isn’t doing anything.

Throwing the C1131-92 warning.

I’m struggling to believe it’s the compressor with the rear raising so effortlessly.

Any other suggestions before I throw more money/give up and go shop to sort?

Thanks

 

Could be the middle valve block sticking open...

 

Thank you! When I had the compressor replaced the front and rear value block were also replaced. Just checked the invoice and that valve block wasn’t. I’ll get to work and report back!

 

Cleaning and rebuilding with new seals often works btw

 

Raising slowly is usually a compressor with low output or a leak in the air lines or valves. What is the compressor temp when running? what is the compressor motor temp when it is running? try watching the temp and pressures when the compressor starts up and see if iit seems to get hot quickly without a corresponding rise in pressure What is the compressor motor current draw when running? Sometimes the motor will draw a lot of current and overheat and not run at full speed. You say you re-flashed the ECU, Does that mean you told the car it has an AMK compressor? I will keep thinking about this and get back with you if I think of something else.

Jeff

 

OK - so before it's got too dark I've had another play around. Still firing up errors. Cleared all, took for a 10 minute drive and have the following still:

C1A20-64 (AF) - Pressure increases too slow when filling air reservoir - Algorithm based failure - signal plausibility failure.
U0132-87 (0B) - Lost communication with ride level control module - Bus/signal message failure - missing a message.
U0159-87 (2E) - Lost communication with parking assist control module - Bus/signal message failure - missing a message.
U0127-87 (2E) - Lost communication with tire pressure monitor module - Bus/signal message failure - missing a message.

I ran through the live values and the things that stood out to measure:

Barometric pressure - 14.8psi
Compressor Voltage - 13.3v
Compressor Temp - 126F
Gallery pressure - 23.6psi

When the compressor was running earlier, it was around 240F.

The truck hasn't been driven for 2 weeks so the battery is running around 13.5v. Usually it's around 14.1v so wondering if sitting around in the heat wave has killed it a bit and it need a run as well.