So I got myself in a bit of a pickle with the air suspension on my mates C6 Allroad. Initially he reported the yellow warning light coming on and flashing after a short time driving, and height positions locked out of mmi.
I scanned the car and got 02645 "Solenoids For Level Control System" code.
Checked the obvious stuff like relay, fuses with nothing unusual.
Car was still maintaining height ok.
I decided to try a height calibration just incase but when I attempted to I got the failed to adapt error. Then the code became 01437 "Control Position Not Adapted", and there are no longer stored values.
I thought maybe the car was sitting too low, so I used basic settings to charge the front and rear which worked fine. Compressor also charges the reservoir fine.
I still get the fail error when attempting to input heights.
Now it also seems that I cannot lower the car using basic settings. Whenever I try to bleed the front or rear I can hear some kind of mechanical click noise up front, but nothing happens.
Any attempt to bleed the suspension results in code 02646 "Plausibility Level Control".
I even broke out ODIS and ran a suspension diagnostic which returns a "test not ok" error for every component, unless I specify one of the charge tests which carry out fine. So the problem really seems to occur when bleeding / lowering.

I replaced the valve block, but still the same behavior as before. I can clear the codes and only 01437 "Control Position Not Adapted" remains. Then I try to run the calibration sequence (or bleed anything), it fails when I try to write the first value, and then 02646 "Plausibility Level Control" comes up as well.

I took the N111 valve off the compressor to test, but I can't get it to do anything when applying 12 volts to it.

My other thought is that maybe the control unit J197 is corrupted or playing up.

I would greatly appreciate any ideas.

 

I’m probably too late to help you, but just to point out the solenoid valve which allows the level to be lowered is built into the air compressor, close to the front bumper on left hand side of car as you look at the front of the car. (RHS as you sit in the cabin)

You would likely have to take the compressor out to be able to do anything with it. But if the solenoid valve has jammed maybe just tapping it in the right place could help.

 

You saying you applied 12 VDC directly to the compressor and nothing happened? I would say start there! lol

 

No he’s saying the solenoid valve which should open to release air from the system does not move when 12V is applied. So that is confirmed as the source of the trouble.

So it was somewhat redundant for me to inform him where the part was and how to test it, as he had already done enough to confirm why the system wasn’t working.

I am going to assume he’s fixed it by now, with a new N111 or freeing up the jammed one perhaps.

 

A bit long but this series discusses most of the scenario you’re seeing. All the Audi Haters are going to love this 😅

In the end the compressor was worn out and not charging the accumulator fast enough triggering the misleading Solenoid DTC. Audi dealer charged $600 to guided-fault-find and called Compressor which in the end was true, although the control module needed to be replaced as well.

The compressor pulls 18A and can approach 30A when overheating so testing with a 12V source needs enough high current ability to even start the compressor.

 

Remembered this thread today, thought I would just confirm for the record that a new N111 solenoid fixed everything. Was about $20 from China, can't beat that...

It seems that the solenoid is exactly the same as the one used across many Mercedes vehicles, so it may be easier to track down something for that. Here is the MB fitment info from the one I successfully used:


For Mercedes W220 W211 W219 Solenoid Valve Air Suspension Compressor Pump Repair Kits 2113200104 1999-2000 2203200104 2113200104

OEM Number:
2513202504; 2213201704; 2213201604
2203200104; ; 2113200304; A4154031120
A2513202704; A2513202604; A2513202504
A2513202104; A2513202004; A2513201304
A2513201204; A2213201704; A2213201604
A2213200904; A2213200704; A2213200304
A2203200304; A2203200104; A2193200004
A2113200304; A2113200104; A1663200104
A0025427619; A0025422319; 221320090480
221320030480; 221320070480; A221320160480
A221320170480; A221320090480; A221320070480
A221320030480; A211320030480

Fitment:
For Mercedes-Benz S-Class W220 1998-2005
For Mercedes-Benz E-Class W211 2002-2009
For Mercedes-Benz CLS-Class 2004-2011 (W219 CLS55 & CLS63 AMG)
For Mercedes-Benz CLS-Class 2004-2011 (W219 w/AIRMATIC)