So I have a 2002 CLK430 with 205k and had no problems prior to the transmission going into limp mode. Once the check engline light came on the dash I scanned the car to diagnose it and the vehicle code that appeared was P0715 which is the transmission conductor plate. I had ordered the new conductor plate along with the pin adaptor and filter. I take it to a MB indie shop for them to fix and done it was fix. Car started shifting again well. But when I was going back to college which is 5 hours away as I barely got to my destination I stopped to use the restroom at a station. When I came back to turn it on, the check engine light comes on again and then goes into limp mode. I was overthinking ideas of why it would happen again after replacing the conductor plate. From that point on I have no clue to what caused it to go back into limp mode. I even took it to another indie shop so they can remove the transmission code but after I test drove it , it was back into limp mode. He said that the transmission might be slipping but how if it involves the P0715 code?
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So my question is , should I buy a transmission replacement or is there any other solutions all you might know of before I do something costly?

 

Before you replace the transmission, even at an advanced 205K miles, the 722.6 in the W208, is arguably the best MB ever produced. Mechanically, it's been pretty bullet proof, with just about every issue, due to one of the electronic control modules (e.g. conductor plate, transmission control module or shift module). Note: As of vehicles built after April 2001, an updated 'spill resistant' shift module was installed.

What MB engineers did right, was to put the vehicle into limp mode, when the electronics did not communicate correctly. This limited the vehicle speed to 30 MPH, to prevent potential mechanical damage to the transmission.

What the MB engineers did wrong, was to not take into consideration, despite using the latest and greatest synthetic fluid, was the wear and tear a transmission goes through (e.g. metal chips from gearing, deposits from graphite clutches etc.). Even though our owner's manuals specifically stated that the transmission fill was good for life and never required servicing, based on transmission issues, that was soon changed, to service required (e.g. change filter and fluid), initially at 40K miles and ever 40K miles thereafter. Go figure.

When you scanned your limp mode/CEL, assuming a OBDII scanner, the result is very generic (e.g. basically an implausible difference between one or both of the conductor plate speed sensors and the TCU). As noted by Plutoe, the MB SDS system might have drilled down a bit.

Upon searching/reading threads, I understand why you took the 'fire ready aim' vs. the 'aim ready fire' solution.

Many questions.

Is your current fluid level up to specification?

Where the replacement parts purchased, sourced as MB genuine or knockoffs?

Did the independent shops use the MB SDS system to fully diagnose the issue and repair?

Note: When the conductor plate is replaced, only the MB SDS system will clear prior diagnostic trouble codes, to exit limp mode.

Was the 13 pin connector (a.k.a. pilot bushing) leaking? Is the wiring harness in good condition (e.g. no fluid wicking into the TCU and/or wires shorted to ground)?

 

 

I doubt you’re still on this forum, but if you are can you let me know if you ever figured that out? I’m looking for a new wire harness for my 2001 clk 430