A Klasse gearbox issue resolved

My 2016 A Klasse with a gasoline engine is stuck in park and won't start. The check engine light is on, the gearbox is acting strangely, and there are stored error codes. I suspect the control unit. I was quoted 1000€ for the repair. Any thoughts?

4 comment(s)

That sounds plausible given the symptoms. Are there any specific codes related to the shift lock solenoid or the transmission control module TCM? Have you tried starting it in neutral? Slipping could also mean low transmission fluid, but a faulty TCM is more likely with the parking issue.

The codes point to TCM failure. It still won't start in neutral, and the fluid level is fine. The shift lock seems jammed. What's the quickest way to verify the TCM before spending 1000€?

Considering the codes, shift lock issue, and good fluid level, the TCM is the main suspect. Without diagnostic tools like Xentry to directly test the TCM's inputs and outputs, it's hard to be certain. The best approach is to have a qualified workshop properly diagnose the automatic transmission before condemning the TCM. It could be an internal transmission failure, but the TCM is probable.

The workshop confirmed TCM failure. I replaced it, and the gearbox shifts smoothly now. Thanks for the help.

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