PieRat

Car keeps popping out of manual mode and into sport or comfort once engine and transmission get to operating temp. Trans seems otherwise complerely fine. The dealer thinks this is the tcu but I have two amd it persists! I have a faulty brake switch which they're replacing tomorrow. Could this be related?
Any help appreciated!

Cheers

Racin_fool

Doubt the brake switch and transmission mode issue are related. More than likely there is something going on with software or possibly something got into the physical switch near the shifter for changing modes and is giving you hell.

seanol

I have seen that problem on the forum before. It was an oil level sensor going bad. May want to check it.

PieRat

Dealership says there is a temp sensor but no oil level sensor in the trans..Can someone please point me in the direction of a part #

seanol

Oil level sensor is in the oil pan. It has caused issues with transmission operation similar to what you are describing. Search these forums and you will see what I am talking about.

PieRat

Ah engine oil sensor not transmission. Odd that its affects this. Thanks for the help I found a service bulletin using search. Here it is if anyone else needs it.


Order No.: P-B-18.40/39

Supercedes:

Group: 18

SUBJECT:
Model 171.473, Equipped with Engine M113.989
Model 203.065, Equipped with Engine M112.961
Model 203.076, Equipped with Engine M113.988
Model 209.376/476, Equipped with Engine M113.987
Model 211.076/276, Equipped with Engine M113.990
Model 219.376, Equipped with Engine M113.990
Model 230.472, Equipped with Engine M113.995
Model 230.474, Equipped with Engine M113.992

Transmission Mode Changes from M to S


If you receive customer reports in the above model vehicles of the transmission mode changing by itself from M to S/C while driving, the engine oil sensor may be the cause. The engine control unit may contain no stored faults codes or the fault codes shown above. To resolve, install engine oil sensor A006 153 59 28.

tw2

I remember reading about this a while ago, very strange, did they say how it causes it? I don't recall. Of course even stranger is finding the bulletin your tech needs yourself.

PieRat

Someone in one of the threads said that it was because the sensor spazticates, the engine thinks its getting low on oil so the computer tries to take control of the RPM's (I think it was to raise it) by taking control of the transmission back? Explains why the fault occurs most at idling or when letting off the POWER.

oneslow55

I would try a battery reset,it's a amazing what that trick does.

PieRat

Thats helped with a lot oc problems in the past with this car and others. Unfortunately no luck for this issue though.

oneslow55

reset the tcu with star.

jumph4x

Damn, if true these things are entirely too clever for early 00s.

PieRat

Got round to replacing the oil level sensor today. Did it during service since oil needs to be drained. Problem solved.