Erratic Gear Shifting and Grinding Noise in 2015 Peugeot 108: Seeking Advice on Transmission Control Unit Issues

Hey there! I had a similar problem with my 2012 Peugeot 207. I'll spare you the pain but you're right to get ahead of it. My car was doing the gear dance like crazy and there was some nasty grinding noise, just as you said. Took it to my local garage, the mechanic got it hooked up to the diagnostic system and sure enough, the Transmission Control Unit (TCU) was throwing a code. He explained that the TCU controls the gear shifting and a bad one can lead to unpredictable and erratic shifts. Kind of serious issue as it heavily impacts transmission's performance and can cause more troubles if neglected. The bad sucker had to be replaced. As for the process, my car had to be put up with diagnostics, then the old TCU was swapped out and a new one was installed. After that, the system was recalibrated. In short, if your 2015 Peugeot 108 is showing the same symptoms, you could be looking at a TCU replacement. Good luck and let us know how it goes!

Howdy! Looks like my old Peugeot also had a dance partner, albeit an unwelcome one. I had to replace the TCU in my ride too. Your explanation of what happens during the process nailed it, by the way. Just out of curiosity, do you remember what you ended up shelling out for the whole gig - the diagnostics, replacement, and recalibration? Also, since that fix, has your Peugeot given you any other headaches? I'd just love to know if this TCU issue could be a sign of more trouble on the horizon. Cheers!

Hey! Good to hear from you. Yup, that unruly dance partner cost me a fair bit. I ended up paying around 1000.00 €. This was covering the diagnostic testing, the swap-out of the old TCU, the installation of a new one, and finally the recalibration of the system. It wasn't exactly pocket change, but it had to be done, y'know? And I'll tell you what. Since getting that done, the car's been running pretty smooth. No more awful grinding noises, no more erratic gear changes. So, in my case, fixing the TCU seemed to have nipped things in the bud. But like I said, every car is a bit different, so I'd recommend you to keep a keen eye on your Peugeot's behaviour after the fix. Good luck with your ride!

Thanks for sharing your experiences, mates. Looks like I'm heading for more or less the same drill with my Peugeot, a TCU replacement that is. Good to know you ended up with a smooth running car post that though. A 1000.00 € isn't exactly what I'd hoped to shell out, but hey, if it keeps the old girl purring, it's worth it. I'll definitely keep a close eye on her after the fix, just in case she decides to throw me another curveball. Will keep you all posted on how it goes. Thanks for the advice and fingers crossed, no other issues crop up. Cheers!