miafrost1

Mercedes GLS gear indicator problem

My 2016 Mercedes GLS with a gasoline engine is giving me some serious grief. I've got almost 98000 km on it. The gear indicator on the dash is completely dead. I can't shift gears properly, the transmission feels like it's slipping, and I'm hearing some nasty grinding noises when it finally does shift. Plus, I pulled the error codes and there's something stored about the gear selection. Any ideas?

4 comment(s)

The symptoms you describe for your Mercedes GLS, specifically the non-functional gear indicator, shifting abnormalities, and stored error codes, strongly suggest a problem within the transmission control system. Given the integrated nature of modern automotive electronics, an issue within the instrument panel or the gear selector module itself can propagate throughout the system. I would immediately check the TCU (Transmission Control Unit).

TCU? So, is that something I can check myself, or am I looking at a trip to the shop? If it is the TCU, is it a straightforward replacement, or does it need programming or something?

Based on the error patterns you are experiencing, the TCU is most certainly the crux of the issue. While a visual inspection of the TCU's connections for corrosion is within the realm of a DIY check, diagnosing internal faults requires specialized diagnostic tools. Furthermore, replacement of the TCU will necessitate SCN coding to ensure proper integration with your GLS's existing systems. Considering the potential for further complications and the need for specialized equipment, I would advise consultation with a certified Mercedes-Benz technician. A defective control unit can cause consequential damage.

Thanks for the info. I took it to the shop, and you nailed it. The TCU was shot. Ended up costing me around 1000€ for the replacement and programming. Appreciate the help!

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