VW Virtus ABS & Traction Control Warning Mystery

I experienced a similar issue with my 2021 VW Polo last year, so I have some relevant experience to share. The symptoms were nearly identical, constant ABS warning light and traction control malfunction. Initially, I thought it might be just a sensor issue, but the diagnostic test at the workshop revealed a defective control unit that was affecting multiple systems including the ABS and speedometer readings. The ECM was reading incorrect signals which triggered the warning lights. The workshop performed a full diagnostic scan that pinpointed the exact control unit causing the problem. They had to replace the affected unit and recalibrate the system to get everything working properly again. The total repair cost was 1000€ including parts and labor. However, to provide more specific advice for your case, could you share: Have you noticed any other warning lights? Does the speedometer work correctly? When did these symptoms first appear? Have you had any recent work done on the car? These details would help determine if your issue matches what I encountered or if it might be something different. Its always best to get a proper diagnostic scan done, as ABS issues can be safety-critical.

Last service was completed at 35000km and everything worked perfectly until last week. Just checked the speedometer and noticed its showing inconsistent readings, sometimes normal, other times jumping erratically or freezing completely. This matches what youre describing about incorrect signal readings. No other warning lights aside from ABS and traction control. No recent repairs or modifications were done. Seems your diagnosis about the control unit might be spot on, especially since multiple systems are affected. Will get it checked at the workshop. Thanks for the detailed cost estimate, helps with planning the repair budget.

Based on those additional symptoms you described, especially the erratic speedometer behavior, this is almost certainly the same issue I encountered. The inconsistent speed readings are a classic sign of a failing control unit, just like in my case. The diagnostic scan I had done showed the control unit was sending corrupted input signals, which explains why both the ABS malfunction and speedometer issues appeared together. Your situation sounds identical, the unit starts failing gradually, first affecting the speedometer readings before triggering the ABS warning lights. One thing to note, when this happened to my Polo, the workshop mentioned these control units rarely fail in isolation. They checked the entire ABS system including wheel sensors during the repair. While the main cost was the control unit replacement (around 1000€), its worth having them inspect the complete system while theyre at it. Since youre seeing the same progression of symptoms, I recommend getting it checked soon. The erratic speedometer readings suggest the problem is getting worse, and driving with compromised ABS and traction systems isnt ideal for safety.

Thanks for sharing that experience. The erratic speedometer behavior you described matches exactly what Im seeing. Good point about checking the entire ABS system, makes sense since everything seems connected. Will schedule the workshop visit this week since the sensor malfunction appears to be getting worse. The input from the failing control unit affecting multiple systems definitely explains the combination of symptoms Im experiencing. The 1000€ budget estimate helps set realistic expectations for the repair costs. Better to address this now before any safety systems like the ABS become completely non-functional. Will update the thread once I have the diagnostic results and know exactly which control unit or sensor caused these issues. Really appreciate the detailed technical explanation and guidance.