Audi Q5 Won't Start: Engine Control Warning Nightmare

I dealt with nearly identical issues on my 2020 Audi Q3. As someone with some hands-on experience working on cars, I initially thought it was an ECU failure when the engine control warning appeared. After several failed starts and similar clicking sounds, I took it to a workshop. The diagnostic check revealed it wasnt as serious as feared, the battery cable connections were corroded and loose, causing intermittent electrical contact. This was triggering false engine software alerts and the starting problems. The repair took about 1 hour. They cleaned the battery terminals, replaced the connectors, and reset the engine control unit. Total cost was 155 Euro. Since then, no more engine surge issues or starting problems. Before suggesting more specific solutions, could you share: Has the check engine light been constant or flickering? Do you hear the fuel injection system prime when turning key to ON? Have you noticed any corrosion around battery terminals? Are there any other electrical issues like dim lights? These details would help determine if your issue matches what I experienced or if its something different.

My car has 162241 KM and was last serviced 3 months ago. The check engine light has been constant and I do hear the fuel injection system prime when turning the key to ON. No corrosion visible on battery terminals and all electrical systems seem normal. No dim lights or other electrical issues. I checked again today and noticed the clicking sound is coming from the engine bay area, not the starter. Also getting some strange engine diagnostics codes that were not there before. Really hoping its not a major ECU failure, as that would be quite unusual for a 2022 model. Would it help if I shared the specific error codes from my OBD scanner?

Thanks for providing those additional details. Your symptoms are actually quite different from what I experienced with my Q3, despite the similar initial signs. The constant check engine light combined with normal fuel injection system priming points to a different issue than what I faced. The clicking from the engine bay rather than the starter is particularly telling. When my car had the electrical connection problems, the clicking was definitely from the starter area. Since your electrical systems are working fine and the battery connections are clean, we can likely rule out the electrical issues I encountered. The fact that you are getting new engine diagnostics codes is crucial information. Yes, sharing those OBD codes would be extremely helpful. In my experience with Audi engines, the diagnostic codes can quickly pinpoint whether this is an engine software issue or a mechanical problem with the fuel injection system. Since your car was serviced recently, it might be worth checking if any engine control updates were performed during that service. Sometimes engine software updates can conflict with existing ECU settings, causing startup issues.

The constant check engine light and clicking from the engine bay does sound more serious than my initial electrical issues. Thanks for clarifying about the OBD codes, I can share them now. Using my scanner, I got these codes: P0341, Camshaft Position Sensor Circuit Range P0606, ECU Processor Fault P1693, Engine Control Module Fault Since all electrical systems are working and the fuel injection system still primes, these codes suggest its likely an ECU failure or engine control issue rather than a basic electrical problem. Especially concerning is that P0606 code pointing to processor issues. Really appreciate the thorough responses. Going to book it in for diagnostics tomorrow and will make sure to mention these specific codes. At least now I know its probably not just a simple electrical connection problem like you experienced with your Q3. Will update once I know more about the repair needed.