FWIW, I have just discovered a latent service defect courtesy of Mercedes Benz here in SA.
A few years ago my car died while towing and there was a hitch hiker that showed us how to disconnect the airflow sensor. We have not replaced it as funds have been tight and it worked when the car was below 80 deg C.
In this time my headlights up and down adjustment from inside the car also stopped working, merc were not interested in giving us a vacuum schematic, buggers.
Anyway, we had a squiz by removing the controller to start tracing the pipes. The vacuum pipe (a white one) at the back of the intake manifold was nicely tucked away under the bonnet rubber seal but went nowhere.. The is a joint where it goes through the engine compartment firewall and we repaired it with short piece of rubber hose, methinks the engine cleaner guy broke it and hid it like that. The pipes to the controller are a dark pink and purple one but possibly, the white one is faded, the car is 15 years old.
After the fix, everything started working properly again and the engine temp stays below 80 Deg C, I did the transmission reset and wow, what a difference. A simple vacuum pipe not doing anything, screwed up the entire engine.
The pic shows the pipe, (probably flipped for LHD) where we did the fix.
Hope this is of value to other owners.
I have one question, the double kick down (depressing till it activates the kick down switch) does not seem to work in second (could have been third too), does it only work from third onwards? If not what are the steps to fix?
Thanks in advance.