Hi
I have a very odd issue with my A Class and hoping that this might be a know issue.
The car is a an auto transmission and about a year ago the Transmission ECU failed. I had this repaired through a Mercedes certified garage and was then told that the gearbox has burnt out as well. As I was already half way in with the ECU fixed, I agreed to fit a used gearbox with warrated miles. The transmission has 2 modes C (guessing Comfort) and S (Sports). When I drove the car in C mode and tried to start in C mode I get a Display fault error and gear information is not available on the dash. everything else works. I then drove the car for a year on Sports mode and no issues. Last week I send the car for a service and it came back in C mode. I continued to use the car in C Mode for couple of days and this morning I have the same display fault error. I have tried battery reset and the fault is not clearing. I used a Creader ViII reader but this is unable to connect to the engine. In the previous instance when this happened the garage said that they only disconnected and reconnected the gearbox ECU and the car fired up

My questions are:
1. For this particular car model where is the transmission ECU plug located?
2. Is there something else playing up that is causing this issue that I should be looking at?

Thanks
Hansel.