VW Tiguan Dead Silent: ECU Failure Warning Signs

Had a similar issue with my 2012 VW Golf GTI at around 110000km. As someone with moderate experience working on VWs, this sounded very familiar. Initially thought it was an ECU failure too, but after engine diagnostics at the workshop, it turned out the battery cable connections were corroded and loose, causing intermittent electrical contact. This explained the unusual check engine light and starting issues. The poor connection was affecting the fuel injection system and other electrical components. The fix involved cleaning the battery terminals, replacing the cable ends, and running a full diagnostic scan to ensure no engine software issues remained. Total repair cost was 155€ and took about 2 hours at the shop. Before assuming ECU problems, could you share: Are your battery terminals clean and tight? Does the key fob work for locking/unlocking? Do your dashboard lights come on with key in position 1? Any recent electrical issues before this started? These details would help determine if you are facing the same electrical connection problems or if its truly an ECU related issue.

Thank you for sharing these details. With my Tiguan at 26708km and last service completed 3 months ago, I have faced similar starting problems recently. After checking all the points mentioned, I can confirm: Battery terminals appear clean with tight connections, Key fob works perfectly for all functions, Dashboard lights illuminate normally in position 1, No prior electrical issues noticed The engine light behavior matches exactly what I experienced, brief illumination followed by normal operation after restart. Since my mileage is significantly lower, I am wondering if this could point more toward an ECU issue rather than general electrical problems. The fuel injection system seems to work fine when the car actually starts. Could you tell me which diagnostic tests were performed to confirm your electrical issue? Want to ensure I approach the repair systematically before replacing costly components.

Thanks for those extra details about your Tiguan. The symptoms still remind me of what I dealt with on my Golf GTI, even though our mileages differ. While the clean terminals and working electronics seem to rule out basic electrical issues, there could still be hidden connection problems. In my case, the corrosion was actually inside the cable insulation, not visible at the terminals. The diagnostic tests that revealed my electrical issue included: Voltage drop test across major connections, Full ECU scan for fault codes, Fuel pump voltage measurement, Starter circuit analysis The intermittent engine light combined with complete starting failure matches the pattern of an electrical fault more than typical ECU failure. When my ECU had problems previously, it usually triggered constant check engine warnings and error codes rather than occasional flashes. The key test that identified my issue was the voltage drop measurement, showed significant resistance in what looked like clean cables. Might be worth having this checked before considering ECU replacement, which can cost over 1000€. Based on my repair experience, I suggest getting a complete circuit diagnosis done first. Modern engine software and ECU systems usually show more consistent error patterns when failing.

Those details about the voltage drop test and electrical diagnostics are exactly what I needed. The cost difference between checking the wiring and replacing an ECU definitely makes it worth investigating the electrical system first. The fact that your ECU issues showed more consistent error patterns is particularly helpful. My intermittent engine light behavior does match more with your electrical fault experience than a full ECU failure. The fuel injection system working normally when the car starts also supports this theory. I will schedule a diagnostic appointment focusing on the electrical system first, particularly the voltage drop measurements you mentioned. Even though my battery terminals look clean, the possibility of hidden corrosion inside the cables makes complete sense given the symptoms. Will have them run the full set of tests you listed, especially since my engine stalling issues match your previous experience so closely. Much rather pay for proper diagnostics than jump straight to expensive ECU replacement without confirming the real cause. Thanks for helping me avoid potentially unnecessary repairs. Will update once I have the diagnostic results.