Hi all, I have a 2003 c320 

it went into limp mode and stuck in 1st gear 

I can’t locate the aux battery 

any help would be appreciated, going to try trans fluid also 




Look in the center console compartment. Pull out the liner. There should be a hole in the bottom of the compartment. Stick a screwdriver in there and push until you feel it stop, gently that is. Grab the shifter and you should be able to move it into park. Now, that is the emergency shifter release, and that will allow you to take it to get fixed, but you will have to do that every time you drive the car. 

I think your problem is most likely the 13 pin connector that goes into the transmission. Take it out and make sure it has no oil leak. It is on the passenger side of the transmission. 

Also check transmission fluid level.