Does anyone have any good links or information on checking the shift solenoids for an R52? I'm hoping to find some lessons learned / techniques as I'm just now considering this job. This is the best link I've found so far, but it doesn't describe how to actually make the adjustments. I think I have a solenoid issue or an INPA issue, still trying to figure out which one it might be.

My R52 has been stuck in EP since I purchased it almost a year ago. I have a CEL and read the code in INPA as P0977, "Shift Solenoid B Control Circuit High" and with an OBD Scanner I get FC2720 EGS solenoid valve, S2. Also, in INPA, it says the S2 solenoid output state is ON while S1 solenoid output is OFF even though the car is off with the ignition on. I suspect that solenoid output state may be the source of my problem.

I can clear the code and get the car to drive once without EP mode engaging. FWIW, the car drives GREAT that one time. However, every time I cycle the ignition to OFF and then back ON, the CEL and EP modes set when the car is restarted. I have tried resetting the adaptations in INPA, and while it says it worked, the car does not go into learning mode. I suspect this is because the transmission sets the solenoid 2 error so quickly. It could also be because I am doing something wrong in INPA and am not actually get the adaptations to reset even though it says (in German) that it may have worked...

In 2014 the previous owner had a transmission shop replace the valve body with a RevMax body and the car has been driven about 30k miles since. I believe the car has had this ongoing problem ever since that valve body was installed.

 

Anyone offer any help on checking / repairing shift solenoids?