Crossfire Transmission Control Failures & TCM Fixes Revealed

I had a very similar issue with my 2006 SLK, which shares many transmission components with the Crossfire. Speaking from moderate experience working with automatic gearbox issues, your symptoms sound nearly identical to what I encountered. The transmission control module was indeed the culprit in my case. The car computer was throwing multiple error codes related to the gearbox issues, particularly during cold starts. My automatic gearbox would also shift roughly and occasionally slip between gears. After some initial diagnosis attempts, I took it to a specialized transmission workshop. They ran comprehensive tests on the control module and confirmed it was defective. The total repair cost came to 1000€, which included the replacement of the affected control unit and programming. The repair completely resolved the issues, no more rough shifts, slipping, or limp mode episodes. The transmission control has been working flawlessly since then. Before offering more specific advice about your situation, could you share: Current mileage on your Crossfire, When these symptoms first appeared, Whether the issues occur more frequently when the engine is cold or warm, The specific error codes your car computer is showing This information would help determine if your case matches what I experienced and whether similar solutions might work.

My Crossfire has 20370 KM and recently had its annual service. After looking into the transmission repair issues you mentioned, I think our problems are quite similar. My control module also throws error codes during cold starts, and the gearbox issues match what you described. The workshop I consulted suggested the transmission control unit is likely failing, which aligns with your experience. The quote they gave me for replacing the control module and reprogramming was around 1200€, slightly higher than what you paid. Before proceeding with the repair, I plan to get a second opinion from another transmission specialist. The car computer diagnostics already point to the control module, but Id like to be certain before making such a significant investment in the repair. Thanks for sharing your repair outcome. Its helpful to know the fix resolved your transmission problems completely.

Thanks for the additional details about your Crossfire. Based on your mileage and the matching symptoms, I am even more convinced we dealt with the same transmission control module issue. The 1200€ quote seems reasonable for the control unit replacement and necessary programming, prices have gone up since I had mine done. Getting a second opinion is smart, but from my experience with these gearbox issues, the initial diagnosis appears accurate. When I waited too long to address the failing control module, the transmission problems became more frequent and severe. The grinding noises during shifts were particularly concerning. One tip from my repair experience: make sure whoever does the work has experience specifically with these transmission control systems. The programming phase after replacement is critical, it took my shop about 2 hours to properly calibrate the new control unit to the automotive ECU. The investment was worth it in my case. The transmission has shifted perfectly for over 40000 km since the repair, with no return of the previous problems or error codes.

Thanks to everyone who shared their experience with these transmission problems. After getting a second opinion from another specialist, I decided to proceed with replacing the transmission control module. The symptoms and diagnostic codes were too similar to ignore, and I didnt want to risk more serious gearbox issues developing. The repair cost ended up being exactly as quoted, 1200€ for the new control unit and programming. The shop I chose specializes in transmission diagnosis and had previous experience with similar control module failures. They took extra time with the car computer calibration, making sure everything was properly synchronized. Its been two weeks since the repair, and the transmission is working perfectly. No more rough shifts, grinding noises, or error codes. The cold start issues have completely disappeared, and the gearbox shifts smoothly in all conditions. Really glad I moved forward with the fix instead of waiting for the problems to get worse. For anyone facing similar transmission control problems, I recommend getting it checked early. The diagnostic process was straightforward once I found the right specialist, and the repair has completely resolved the issues.