CT5 Owner Reports Critical TCU Failure and Gear Issues

I experienced very similar transmission problems with my 2020 CT4, which has practically identical transmission components. With some experience working on modern vehicle electronics, I recognized the classic signs of a failing control module. The transmission diagnosis revealed the control unit was indeed defective, causing erratic shifting patterns and those concerning grinding noises. The electronic issues also triggered the emergency mode, much like your situation. The repair involved: Complete diagnostic scan, Removal and replacement of the transmission control module, Reprogramming of the new unit, Full system calibration Total workshop time was about 6 hours, and the final cost came to 1000€ including parts and labor. The gearbox issues were completely resolved after the repair, and transmission performance returned to normal. Before suggesting specific solutions, current mileage on your CT5, Whether any transmission maintenance has been done previously, If the check engine light is on, Which specific error codes are showing, Whether the problems started gradually or suddenly This information would help determine if your situation matches what I experienced with my transmission diagnosis and repair.

Had my last service just 2 weeks ago at 25549 KM. The car computer diagnostic showed multiple transmission control module faults, but the service center wanted 2500€ just to start investigating. Seems excessive given other repair experiences shared here. The transmission problems persist despite regular maintenance. Would appreciate hearing about reliable independent shops with experience handling these electronic issues.

Thanks for the additional details about your CT5. Having gone through this exact issue with my car, I can confirm that 2500€ for initial diagnosis is absolutely excessive. The car computer diagnostic already pointed to transmission control module faults, which matches the symptoms perfectly. The gearbox issues you describe are textbook transmission control unit problems. When I had my repair done, I specifically sought out a workshop specializing in automotive ECU and transmission repair. They charged 150€ for a comprehensive diagnosis, which included full electronic fault code analysis. Based on the low mileage of your CT5 and recent service, the transmission control unit failure is likely a component issue rather than maintenance-related. My repair experience showed that waiting too long with these electronic issues can lead to additional transmission damage. Key points from my repair that might help: Full diagnosis cost: 150€, Parts (new control unit): 600€, Labor including programming: 250€, Total repair time: 6-8 hours Look for shops that regularly handle transmission control modules and have proper diagnostic equipment for these specific gearbox issues. The repair itself is straightforward if done by qualified technicians with the right tools.

Those costs and repair times seem much more reasonable compared to the dealer quote. Given my car is still fairly new at 25549 KM, I will definitely look for an independent shop with transmission diagnosis expertise rather than paying 2500€ just to start investigating at the dealer. The transmission problems you described match mine exactly, particularly the car computer showing those control module faults. Good to hear replacing the transmission control unit fully resolved the issue. I will make sure to find a workshop that specializes in electronic transmission repair and has experience with these specific gearbox issues. Based on your repair experience, I will budget around 1000€ total and plan to have the car in the shop for a full day. The grinding during gear changes is getting worse, so I want to get this fixed before any additional transmission damage occurs. Thanks for breaking down the actual repair costs and process, this helps tremendously with knowing what to expect.