C200 5 Spped Auto Problems (electrical ?)

[Graham C200]

I have a C200 5 speed Auto Tipronic with a transmission problem.

Intitialy the car would not start at all or move out of park. Various lights were on on the dash and when the W/S mode switch was moved the reverse lights came on (with the selector in park).
My wife reported that childrens juice may have been spilt around the centre console.
I have stripped the selector out and cleaned up all of the connectors etc.
The situation now is that the car will start and will allow me to go back through the selections into drive with the foot brake applied.
When going back up it will only allow me to go from neutral in reverse when the footbrake is not applied (if the footbrake is applied it will not allow this).
The gear position indicator on the dash is solidly lit (not indicating any gear).
When the car is driven it will not change up (stuck in first ?) even with the tipronic change.
Any thoughts at what I could do or am I stuck with the option of visiting a main dealer ?.

BTW The chassis number is wdb202 080 2F8 97***

Thanks
Graham

 

[Parrot of Doom]

What did you clean the electrical connections with - or did you only clean the connectors?

 

[television]

This is going to be a hard one as you have an electronic selector lever module.
Sugary drinks are the worst as the whole system is CAN bus controlled, we all know from the threads with the Brake light switch how the slightest leak renders the whole system out of order. this is much worse and more complicated.


Maybe some fault code clearing will help if this is possible.

Malcolm

 

[Graham C200]

I used a switch cleaner to clean the connections. I was amazed when I took the central cover off to find an exposed circuit board with no attempt whatsoever made by MB to proof this from any kind of accidental spillage/dust/condensation.
I have only had the car a couple of months and I have a feeling that this is going to be a very very expensive problem to fix.

 

[television]

Once again this is a hard question. I have been in the electronic service industry for 56 years, spills into these things are idividual, when this happens with the circuits all live,voltages can be sent to other circuits where no voltage should be present,only signals and info.
Expensive is hard to say,we wash boards and clean, and test down to component level, MB do not do this and often replace everything wether its needed or not to prevent comebacks. The CAN bus (high speed dator) is sensitive, a fault or short anywhere stops the car .

On th PCB that you can see, is there any residue of the drink on it, if everything is locked up by the CAN bus you could disconnect the battery for 10 mins, but do so with the windows and roof closed, it may reset itself. you have nothing to lose.

Malcolm

 

[Graham C200]

My mechanic friend has stripped the unit out and cleaned up everything he could see. This did improve the situation insofar as the car can now be moved into the gears (although with a clunk).
I did try disconnecting the battery but only for about 20 seconds. I did note that the time on the dash was still correct when I plugged it back in but I assumed that there may be an internal battery which hold data such as the odo mileage etc.
I will give the diconnection another go but will leave it off for a good half hour and see how that works. The centre consol is still out. Should I reconnect the window and mirror switches before taking the power off ?.

Cheers

 

[television]

All data will not be lost with battery off as it stored, you only reset ESP and windows when re connected, you have nothing to lose at this stage. though the gearbox ECU is key cleared of fault codes, I do not know about the rest of it as you have the electronic gear shift, this is canbus connected to the ETC control module,electronic gearshift module,traction systems control module and the EIS (ign switch and DAS) all of these 4 things work together.

My car has a cup holder right over the top of the gear shift and switch bank,as I understand it, not many chance using it

Malcolm

 

[Graham C200]

In the end this was a problem that I got an auto electrician to sort out.

The ECU required resetting after he had stripped the unit down further and removed all traces of crap from around the switches.

The guy who sorted it stated that although the root cause could have been the accumulation of dust and grime, it was as likley that an aged battery could have caused the ecu to do something odd when the voltage dropped when starting the car.

To quote him 'I doubt the people that design these things know why they wrong when they do'. Wise words indeed !.

He also told me of a Taxi firm around the corner who have three Mercs. Resetting their ecu's at £40 a time pays for his holidays apparently !

Anyway, £125 later and the car was back on the road.

 

[television]

In the end this was a problem that I got an auto electrician to sort out.

The ECU required resetting after he had stripped the unit down further and removed all traces of crap from around the switches.

The guy who sorted it stated that although the root cause could have been the accumulation of dust and grime, it was as likley that an aged battery could have caused the ecu to do something odd when the voltage dropped when starting the car.

To quote him 'I doubt the people that design these things know why they wrong when they do'. Wise words indeed !.

He also told me of a Taxi firm around the corner who have three Mercs. Resetting their ecu's at £40 a time pays for his holidays apparently !

Anyway, £125 later and the car was back on the road.

Thanks for posting back, at least the bill was not too big