Fiesta Gear Shift Indicator Failure

I'm having a strange issue with my 2021 Ford Fiesta diesel. At 49566 km, the gear shift indicator display isn't working. I can't engage the gears, the automatic transmission shifts weirdly, the gearbox is slipping and shifting uncleanly, there are grinding noises when shifting, a stored error, and the gear selection display in the speedometer is dead. Diagnostics suggest a defective control unit. Anyone seen this before?

4 comment(s)

That sounds like a headache. I haven't seen that exact issue, but those symptoms point to something wonky with the electronics controlling the transmission. What's the specific error code? That could help narrow things down. Also, have you checked the battery voltage? A weak battery can cause weird electrical glitches in modern cars.

Thanks! The error code is P0702 - Transmission Control System Electrical. Could a slightly reduced voltage cause these malfunctions?

P0702 confirms it's an electrical issue in the transmission control system. Yes, a slightly low battery voltage can cause a lot of seemingly unrelated problems in modern cars because the computer systems are very sensitive to voltage fluctuations. However, with that error code and the severity of the symptoms, it's probably more than just a battery issue. Get it to a workshop with the right diagnostic tools so they can properly test the control unit and wiring harness.

Thanks for the help! Following your recommendation, I went to a workshop. They confirmed a defective transmission control unit and replaced it. The total cost was 1000€. Thanks again for the insights!

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