Funny thing you mentioned that this all happened after a car wash. We just had heavy rain this past week to the point that the streets were flooding and my 2004 9-3 was at one point in water that was as high as the sidewalk.
Sadly, my check engine light came on this week and when I hooked up my reader I got the following codes:
I think its somewhat related to your P2135 code because it behaves very similar to what you described.
So this may be a sign that these pedal voltage related codes are caused by water exposure.
If water truly IS the cause, then I think we could rule out the possibility that this is caused by a faulty wire harness or any other physical damage / splicing in the wires themselves - i.e. no need to be wiggling wires or taking off the wire harness / protective wrap. Also - the water in this case would have most likely come from below so it may be the case that the damaged section of the circuitry is that which is located in an exposed section of the car's underbody down near the street - i.e. not located in any part that is up above by the engine where it is safely covered from water by the hood.
Of course, this is just my own analysis and I could be jumping to conclusions, but I'm just trying to contribute with my own evidence and logic as much as possible.
Been a few months since any of your posts. Any new discoveries? I look forward to joining in the efforts so that we can all find out the proper solution.
Is there anything that has not yet been attempted to solve these issues? I'm ready to roll up my sleeves and try working on this but don't want to repeat the same things others have done to no avail.
Please lets keep this discussion going!
Here are my symptoms: Check engine light turns on and car was drives slow, not responsive when pedal pressed down (Limp Home Mode). Check engine light turns off on its own overnight and drives fine next day at first but then check engine light turns back on and pedal becomes unresponsive again (back into Limp Home Mode).