Peugeot 208 Transmission Issue

I've got a perplexing issue with my 2020 Peugeot 208 diesel. It's done 138492 km. I suspect a defective transmission control unit. Shifting isn't possible via the paddle shifters, the gearbox exhibits slippage and unclean shifts, grinding noises are audible during gear changes, the paddle shifters are slow to respond, and the gearbox has entered emergency mode. Plus, there's an error code for the transmission system. Has anyone seen something similar and have any ideas?

4 comment(s)

Based on those symptoms, a malfunctioning transmission control unit (TCU), also known as the transmission control module (TCM), is the most probable cause. The TCU is an electronic control unit (ECU) that governs the transmission. Slippage, unclean shifts, and emergency mode activation all point to this. Have you done any diagnostics beyond reading the error codes? Have you checked the wiring harness and connectors leading to the TCU for corrosion or damage?

Thanks, I've visually checked the wiring harness and connectors leading to the TCU and found no obvious corrosion or physical damage, but I haven't done any electrical testing of the wiring. What electrical tests would help diagnose the TCU?

Since you've visually inspected the wiring, further electrical tests would involve using a multimeter to check for proper voltage and ground at the TCU connector pins, and checking the continuity of the wiring harness to rule out open circuits or shorts. Given the complexity, I'd recommend a qualified workshop for a comprehensive diagnostic assessment. The symptoms indicate a faulty TCU, and it may need specialized tools for replacement and reprogramming.

I appreciate the guidance and confirming my suspicion. A workshop confirmed the defective TCU. The replacement and reprogramming will be about 1000€. Thanks for your time.

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