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linasilver61

C8 Transmission Control Unit Failure

I'm having trouble with my 2009 Citroen C8 diesel. It has about 97000 km. I think the transmission control unit is bad. The paddle shifters don't work, the gearbox slips, and there are grinding noises when shifting. The paddle shifters are slow, and the gearbox goes into emergency mode. There's also an error stored. Does this sound like a faulty control unit?

4 comment(s)

richardtiger3

Sounds familiar. I own a C8 too, and had almost the same thing. Paddle shifters acting up, gearbox feeling like it's rowing through treacle. Emergency mode is a pain, isn't it? Does the error memory point to anything specific, like a TCU malfunction code?

linasilver61 (Author)

The error code does indicate a potential issue with the TCU. Did you have to replace the control unit, and did that fix the problems? What did it cost?

richardtiger3

Yep, TCU was the culprit. Bit of a nightmare. After a lot of head-scratching and diagnostics, replacing the unit sorted it. You could try checking all the wiring and connections first, but based on your symptoms and error code, I'd say you are looking at a new TCU. Get a quote from a decent workshop; it's not a cheap fix but needs doing right.

linasilver61 (Author)

Thanks. I'll schedule an appointment at a workshop for a diagnosis and TCU replacement. It looks like it will cost about 1000€.

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