Hi there, I am looking for some help on isolating the problem with e320 with 105k miles....

It all started a few weeks back with my wife complaining that the car goes in limp mode every now and then. I first thought it may have some thing to do with fuel line as she lets it go all the way to reserve before filling. So I changed the fuel filter. Did not make any difference and the car still goes into limp mode.


Now to the error lights/codes...

CEL code was the infamous P2335 so started investigating the Exhaust gas system. Dealer suggested changing EGR valve, but The shop foreman suggested checking the EGR admission pipe for coking. Sure enough that was the issue as the carbon buildup had completely blocked the pipe. Cleaning that took care of the P2335 codes and CEL for a bit (see below)

As for the other lights the dealer thought they were related to the EGR system so removed the codes and let me drive. It worked for a day and then the ESP and traction lights came on.

Now I have the CEL back on with the U0101 code suggesting lost connection to TCM. I have a couple of questions on this...

- how to isolate that it is the TCM or the conductor plate that has gone bad?
- I understand that this car has 7G 722.9 transmission. Is there a way to tell ( without opening it) as to which version of VGS does it have? It seems that in VGS1, it is an integrated system and will need to change out plate and valve together if that is indeed the issue. Any thoughts on finding the VGS version?
- finally, could it be something simpler disguised as the TCM fault?

Symptoms
- first drive out in the morning is in limp mode. Comes out of it once the engine is warm. Then slips in and out of limp mode.
- this is very similar to what it was before cleaning the EGR system. The only difference now is a new CEL fault code.
- smoother idle now than before cleaning the EGR pipe.

thanks a lot for your help