E320 CDi W210 gearbox stuck in 2nd (limp)

[Capperdog]

Yes, yet another one....

I’ve seen many similar threads here over the last few months. When starting from cold occasionally the car would stick in 2nd, but running the engine for a while and then restarting always sorted the problem.

About 2 months ago it stayed in 2nd however many times it was run and restarted. So took it to a local MB indi who “checked g/b level – ok, checked ECU contamination – ok, carried out short test, inspected stop light switch and replaced, erased fault codes and road tested – all ok”.

And it was well for 6 weeks but then the car “rested” at a main dealer for 2 weeks to have a lot of body work done. Yes the usual rust problem with these cars, new wings, new tailgate, doors and both rear wings repaired. Thankfully all done under the “good will” warranty scheme and the car does look really nice now...

Anyway since picking the car up it will not change out of 2nd whatever combination of running and restarting. Have checked the battery voltage at +14v but noticed it did need topping up with distilled water, did this and charged battery overnight. Still no change, voltage is good before and after starting several times.

Is it possible that fault codes are stored up in some kind of history but gets full to a point where they are not reset however you try to restart the car? Is there anyway us mere mortals can reset/clear these codes by some combination of button pushing and key turning, whilst standing on one leg, winking and singing the German national anthem?

Any help gratefully received – prior to yet another expensive trip to the MB money drain.

 

[Xtractorfan]

There is a chance that the battery voltage has dropped and went flat during the bodywork repairs, you should have gone back immediately and had the codes read at the expense of the garage... best bet is to try speaking to the bodyshop guy and the Mb garage and hoping they will reset the ecu for you...

 

[Capperdog]

Thanks Xtractorfan but bit difficult because of distances involved and yes the car was driven a long way in limp without the driver noticing, don't ask.... Plus hindsight is wonderfull, we are where we are and can't now go back "immediately".

I'd guess the voltage did drop during the bodywork repairs, but even with the voltage restored the problem remains. Which brings back the original question: is there some way of clearing these fault codes ourselves?

 

[television]

There is a known fault that is a loose connector on the ECU that could cause this,,so could the dear selector module,, there will be some codes stored

 

[Alex Crow]

if the battery is the original, it may be worth changing anyway.

the voltage test to undertake, is to monitor the volt drop DURING START UP. ideally with an anologue meter. if it dips below about 10v change the batt. the scenario which you are obviously well aware of is all about that lowest voltage on startup. the gearbox ecu monitors the voltage available to the solenoid valves, if it dips too far it stores an appropriate code and goes all limp (home).

another test is to start it 20 times in a row, or turn on all lights and fog lights, and watch the voltage fall. but if the battery is 7 or more years old it has done very well anyway, change it.

btw MB batteries have a four digit date stamp on the terminal, first two digits are the week, second two the year.