ATS ABS & Traction Issues Point to Speed Sensor Fault

Had similar symptoms on my 2014 Cadillac CTS with the speedometer giving incorrect input and ABS acting unpredictably. The diagnostic tests revealed a failing control unit that was affecting both the ABS system and speedometer signal. The main issue was the ABS module which required replacing after running a full diagnostic scan. The odometer readings were also inconsistent, indicating the connection between the speed sensors and control unit was compromised. This affects multiple systems since the ABS module provides critical input to various vehicle functions. The repair involved: Full diagnostic scan of ABS system, Testing all wheel speed sensors, Checking wiring harness integrity, Replacing the ABS control module, Recalibrating the new unit This was a serious repair requiring specialized equipment to properly diagnose and fix. The original symptoms got worse over time, eventually affecting vehicle stability control. Would recommend having a certified shop perform comprehensive diagnostic testing focusing on the ABS module and speed sensor circuits first. The repair resolved all issues, proper speedometer function, ABS performance, and traction control were restored to normal operation.

Thanks for sharing your experience. This sounds exactly like what I am dealing with on my ATS. The diagnostic steps you outlined help explain why my speedometer readings have been inconsistent. I took it to a shop last week and paid 180€ just for them to tell me the transmission was fine, which clearly wasnt the root cause. Did the repair fully solve your dashboard issues? And do you remember roughly what the total cost was for fixing everything? I want to make sure I am prepared before taking it back to get properly diagnosed.

Thanks for asking about the follow-up. After getting the ABS control unit replaced and properly diagnosed by a qualified shop, all dashboard warning lights cleared completely. The speedometer and ECM are now receiving accurate speed signal input, which resolved the erratic behavior. The total repair came to 1000€ for the affected control unit replacement, including diagnostic testing and recalibration. While this might seem expensive, it was worth getting it fixed properly rather than continuing with intermittent sensor issues that could compromise safety systems. The repair completely resolved the original symptoms: No more ABS warning lights, Accurate speedometer readings, Proper traction control operation, Normal dashboard function Much better to address these electronic control module issues properly rather than trying partial fixes that dont solve the root cause. The diagnostic testing your previous shop did might help rule out transmission problems, but the speed signal fault clearly needed deeper investigation.

I took your advice and found a certified shop that specializes in ABS systems. The diagnostic revealed exactly what you described, a faulty ABS control module causing incorrect input signals. After seeing how the original symptoms matched your experience, I felt confident proceeding with the full repair. The total cost came to 950€ including: Complete diagnostic testing, New ABS module replacement, System recalibration, Labor costs Much better outcome than my first repair attempt. The ECM is now receiving proper speed signals and all systems are working normally. No more warning lights or traction issues. The speedometer readings are consistent and the ABS functions as it should. Definitely worth paying for the proper diagnostic work rather than quick fixes that dont address the root cause. The experience taught me the importance of finding shops with the right diagnostic equipment for modern vehicle electronics. Thanks for helping me avoid more wasted repair attempts.