georgiabenz

My vehicle is a 2009 Mercedes E350 with 121,000 miles. I am posting in the 212 forum because I couldn't find anything about the 722.9 tranny in the 211 forum. Three weeks ago the car went into limp mode (or basically started in 2nd gear and wouldn't shift). I read the codes with mt Autel MD805 and got the 0748 code on the transmission and a dozen low voltage codes or voltage too low to read etc.
Next morning car would barely start. I checked the battery and it was less than 11.8 volts on full charge and was about 6 years old so I replaced the battery. I read and erased all of the codes and let the car sit overnight. When I drove it the next morning the car shifted and drove fine, no more P0748 or low voltage codes and no codes in the transmission module.
Then, 4 weeks later the car went into limp mode again and I got P0748 again and also a Brake Light Switch code, and the ESP light was on. I cleared the codes but they both came back immediately. Now, I don't get the P0748 code anymore, it just says that the MD805 can't communicate with the transmission module. I was told by a local indy to raise the car to check the connector. It is full of oil.
Here is my question (and of course I will gladly welcome any help), I have changed the 13 pin connector a dozen times on the W210's I have had through the years, but this connector is different. It doesn't appear to be removable. Can I just change o-rings or do I have to get another conductor plate?
Any help will be appreciated. I have attached a pic of the connector.

300SE1993

I can offer something that may help - brake light switches are cheap, easy to replace, and can cause ESP/ABS/BAS errors. I would start there. But seeing the oil in your pic, I don't think that's the whole problem. Someone else more knowledgeable would have to chime in on the connector.

mercy-me

No direct knowledge to share. I'm posting based on my '12 E350 Vin number. If you want an accurate EPC lookup for your car, post your Vin.

From what I can see, the leaking connector is part of the so called Conductor Plate control unit and can not be replaced on its own. It does however have O-rings which would be replaceable. It appears that the conductor plate is held into place by the main control unit which also has replaceable O-rings as well between their interface. Again, no personal knowledge. I have never worked on the valve unit or conductor plate except to have replaced the connector plug on two of my 722.6 transmissions in the past. If you decide to change out the O-rings it would be a good time to do a trans fluid/filter drain and fill as you will no doubt not want to reuse the old fluid. Just change out the filter and change the gasket then button it up and pump in 5 liters run to 45° C then screw in plug when it just dribbles out.

Anyway good luck. Post up your success story,

Bob