Mercedes M Klasse transmission issue resolved

My 2013 Mercedes M Klasse diesel with 255020 km on the clock has an automatic gearbox acting up. Paddle shifters are unresponsive, shifts are slipping and feel unclean, and there's a grinding noise during gear changes. The paddle shifters also have a very slow response time, and the gearbox seems to be stuck in emergency mode. A code reader shows an error related to the transmission control unit. I suspect a defective transmission control unit. Has anyone dealt with something similar? What's involved in a transmission diagnosis, and how can I confirm the automotive ECU is the culprit?

4 comment(s)

Sounds like a potential transmission control issue. Have you checked the wiring and connections to the transmission control unit?

I haven't specifically checked the wiring. Is there a specific area I should be looking at for common issues, or is it more of a general visual inspection for frayed wires and loose connections? Also, could a faulty sensor cause similar symptoms, or is the transmission control unit the most likely suspect given the error code?

A visual inspection is a good starting point. Given the symptoms and error code, a faulty transmission control is highly probable. Take it to a workshop for proper diagnosis.

Thanks for the advice. I took it to a trusted workshop for transmission diagnosis. They confirmed it was a defective transmission control unit. Replacement and reprogramming set me back about 1000€. Runs like new now.

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