VW Polo's Multiple Electrical Failures Point to Bad ECU

As someone with intermediate repair experience, I dealt with almost identical symptoms on my 2009 VW Golf diesel. The malfunction indicator would out of nowhere illuminate, and multiple control module failures occurred simultaneously, particularly affecting the entertainment system. After several diagnostic attempts, my workshop found the root cause: a damaged cable connection to the control unit that interfaces with the vehicle BUS system. The intermittent connectivity was causing various systems to lose communication with the main control module. The fix required carefully tracing the wiring harness and replacing the damaged connection points. Total repair cost was 155€, including diagnostic time and parts. The problem never returned after the repair. For a more accurate assessment of your situation, could you share: Have you noticed any correlation between these issues and weather conditions? Are the problems more frequent when the engine is cold or warm? Which specific error codes appeared in your OBD-II scan? Does wiggling any particular part of the dashboard make the symptoms better or worse? These details would help determine if your Polo is experiencing the same electrical connection issue as my Golf did.

Last system service was done at 65000km, and Im noticing these electrical issues are getting worse with time. During cold starts, the warning signals appear more frequently. The OBD-II scan revealed the following codes: P0603 (ECM fault), U0001 (CAN communication fault), and U0140 (lost communication with body control module). When checking the dashboard area, the warning lights flicker more intensely if I press around the center console. I also noticed a slight correlation, the system failures happen more often during damp weather conditions. Could the moisture be affecting some connections? Based on this, do you think its the same wiring issue you encountered?

Thanks for those additional details. Given the similarity of symptoms and especially your observation about the dashboard pressure point, I am now even more convinced you are dealing with the same wiring harness issue I had with my Golf. The correlation with damp weather and cold starts is particularly telling. In my case, moisture was indeed seeping into a corroded connection point in the main wiring harness, causing those sporadic system failures and check engine warnings. The error codes you listed match exactly what my OBD-II scan showed before the repair, particularly that U0001 CAN communication fault. This indicates a break in the network that connects your vehicle control modules, just like in my situation. Since pressing the center console area triggers more intense warning signals, I suggest having your workshop focus their diagnostic efforts there first. The service required will likely involve: 1. Removing the center console trim 2. Inspecting the wiring bundle for corrosion or damage 3. Testing continuity at connection points 4. Replacing any compromised sections The repair should cost roughly the same as mine (around 150-160€) assuming similar damage. Make sure they thoroughly check all connection points since partial repairs often lead to the same issues returning within months.

Thanks for the detailed explanation regarding the wiring issues. The error codes and symptoms you described with your Golf match my Polo situation exactly. I had my mechanic look at the center console area today based on your advice, and sure enough, they found corroded wiring connections right where the warning lights would flicker when pressed. The scan tool readings make much more sense now, especially those U0001 and U0140 communication fault codes. They estimate about 160€ for the complete repair, including replacing the damaged wiring sections and checking all nearby connection points. Will schedule the work for next week. Really helpful to know the correlation with damp weather and cold starts was the same in your case. The malfunction indicator symptoms and multiple system failures definitely point to this being the root cause rather than individual component issues. Will update once the repair is done, but feeling much more confident now about the diagnostic direction. Beats replacing unusual parts hoping to fix the electrical gremlins.