Audi S1 ECU Fault Code Refuses All Reset Attempts

Had a similar issue with my 2018 Audi S3 2.0 TFSI. The persistent fault code turned out to be an undervoltage condition in the control module circuit. Auto repair diagnostics revealed that standard code clearing procedures were ineffective because the root cause remained active in the system. The fault memory kept recording the issue because the voltage supply to the ECU was unstable. After thorough automotive diagnostics, the problem traced back to a deteriorating ground connection and a failing voltage regulator. The car electronics were getting inconsistent power, causing the control unit to record faults continuously. Despite the engine running normally, this was a serious issue requiring immediate attention. Left unaddressed, irregular voltage supply can damage sensitive electronic components or cause unpredictable system behavior. The repair required cleaning and securing all ground points, replacing the voltage regulator, and performing a complete reset of the active memory. After the fix, fault codes cleared permanently and the system stabilized. For persistent fault codes like this, professional diagnostic equipment is essential to identify the actual voltage fluctuations in the control circuits.

Thanks for sharing your experience. My issue turned out very similar. After the control unit kept locking the fault memory, I finally found a specialist who identified a corroded ground connection near the ECU diagnostics module. Really glad you mentioned the voltage regulator since thats now on my watch list too. Quick question, do you remember the repair costs? Also wondering if youve had any similar car electronics issues since the fix?

Thanks for asking about the costs. The complete fix for the undervoltage issue came to 240 Euro, which included cleaning the corroded connections and replacing faulty components. The car electronics have been running perfectly since the repair, with no recurring fault memory lock issues. The automotive diagnostics confirmed that once the voltage supply was stabilized, the active memory cleared properly and stayed that way. It was worth getting it checked by a specialist who could properly identify the root cause using professional diagnostic equipment. This type of electrical problem often starts small but can escalate if left unchecked. The initial fault codes were really just symptoms of the underlying voltage irregularities. Since the repair, the control unit has been operating as intended with no new fault codes appearing.

After getting multiple fault codes and realizing the control unit kept locking up, I took my Audi to a specialized workshop. The ECU fault turned out to be exactly what was described, a bad ground connection causing voltage issues. The automotive diagnostics revealed this was affecting multiple systems. The technician used advanced testing equipment to track down the voltage fluctuations. After cleaning the corroded ground points and checking the entire circuit, they performed a complete reset of the active memory. The repair cost me 320 Euro total. Its been 3 months since the fix, and the fault memory has stayed clear. No more persistent codes or control unit issues. The engine runs even smoother now, which I hadnt expected. Made me realize how important proper voltage supply is for modern car electronics. For anyone facing similar ECU diagnostic problems, get it checked properly instead of just trying to clear codes repeatedly. The underlying issue wont fix itself.