NoahWeb

Greetings team!! Earlier today while driving home, I discovered that the transmission remained in 7th gear after stopping at a light. This despite using the paddle shifters to aim for a lower gear. Thankfully I made it to the garage and nearly up the driveway. I used a scanner and pulled a generic code of P2768, which is associated with “Input/Turbine Speed Sensor B circuit intermittent.” I believe this is indicative of valve body failure, but am not sure. Has anyone else had a similar problem??

NoahWeb

As an update, Mercedes traced this fault back to faulty wheel speed sensors. All four sensors were replaced, along with two brackets, and the issue seems to have been resolved. As an added bonus, the R63 shifts cleaner and with more precision/confidence than previously. Suspect that the TCU and/or ECU were getting bad data from the sensors and it couldn’t reconcile the differences thus entering limp home mode.

All fixed and back running.

Mark-Hans

Greetings. I am driving a 2006, A209, 350CLK with a 722-9 Automatic Transmission. Two years ago, I got an intermittent problem with the gearbox getting stuck in various gears. By stopping the car, counting to 30, restarting, the system went back to normal. Over time, this fault has increased to a point when the system finally went into Default Mode, or get you home mode only. The car is 60,000 miles old. I changed the transmission filter etc, but noticed that the multi-plug, now set higher on the gearbox & pointing to the rear (so an update on the earlier 722 transmission), was wet!. I dried it off using brake cleaner, both on the plug on the gearbox and the plug that pushes in with a dust cover ring inside of it. The System reported a Speed Control Sensor in the box and was reset. All was well for three weeks, perfect. Yesterday, while driving, she got stuck in 7, so stopped the car, restarted and all went back to normal. It appears that there was fluid creeping up the multi plug. The actual Electronic Control Unit is apparently working fine. Is there a fix for leaking pins?, or does this mean I have to take the ECU out of the box and replace it. I've directed this question to this forum, because I believe there are many people driving this gearbox!. Many thanks for your reply.......

Update. I put my MB on the bridge and again removed the multi plug. This time is was still absolutely dry!........ so that doesn't seem to be the problem. System is running normally again, but I don't trust it. Before I tear down the box to ECU level, is there something I might be missing somewhere else?