Audi Q2 Starter Issues: Electrical Circuit Investigation

Had a similar issue with my 2021 Q3 last winter. With some basic experience working on cars, I initially thought it was the starter, but it turned out to be more complex. After checking the basics like the battery connections and voltage, the workshop found a damaged wiring harness near the starter solenoid. The insulation had worn through, causing intermittent connection issues. The voltage drop across the ignition switch circuit was way out of spec when tested. The fix involved replacing a section of the wiring harness and reconnecting it properly to the starter solenoid. Total cost was 95 Euro including parts and labor. Since then, no starting issues at all. Could be something similar in your case, but to help better, could you share: Any warning lights on the dash before this started? Does the fuse box show any blown fuses? Can you hear any clicking when turning the key? Have you had any recent work done near the engine bay? These details would help narrow down if youre dealing with a similar wiring issue or something else entirely.

Last service was at 125750 KM. Thanks for the detailed response. I checked again today, no clicking sound when turning the key. The relay switch in the main fuse box under the hood appears functional. Had the car scanned and got P0615 and P0617 codes. These point toward the starter circuit, but interestingly all fuses are intact. I notice voltage drops from 12.6V to about 11.8V when attempting to start. Will have the wiring harness inspected as you suggested, since the symptoms match closely with your experience. No warning lights appeared before this happened. Quick follow-up, did your repair require removing any major components to access the damaged section?

Based on the codes you mentioned (P0615/P0617), it definitely sounds similar to what I experienced with my Q3. To answer your question about component removal, yes, accessing the wiring harness required removing the air intake assembly and some protective covers, but nothing too major. In my case, the voltage drop you described (12.6V to 11.8V) was almost identical. The workshop traced it to where the wiring harness runs near the starter solenoid, which required some careful inspection to find the worn spot. Since your relay switch and fuse box components check out okay, and theres no clicking from the starter solenoid, Id bet youre dealing with the same wiring harness issue. The lack of warning lights before failure is another matching symptom. One thing to check before taking it in, look for any signs of rodent damage near the wiring, as this can cause similar symptoms. The repair should be straightforward for a qualified tech, likely in the 100-150 Euro range depending on how much of the harness needs replacement. Make sure they check the ignition switch connections while theyre in there, mine had some minor corrosion that they cleaned up during the repair.

Thanks for your detailed feedback. Hearing about the component access details is really helpful for planning. The matching voltage drop patterns and error codes make me more confident its a similar wiring harness issue. I did a visual inspection around the accessible wiring areas and found no obvious rodent damage, but some of the protective covering looks worn. Given the circuit break symptoms and matching diagnostic codes, I will schedule the repair soon. My main concern was having to remove the entire starter assembly, so its good to know that mainly just the intake and covers need to come off. The price range you mentioned also helps set expectations, seems reasonable for the work involved. Will make sure they inspect the ignition switch connections too since that could contribute to the voltage drop issue. Car wont start reliably anyway, so better to have everything checked while they're working on the wiring harness. Will update once I get it fixed in case others run into similar starter circuit problems. These P0615/P0617 codes combined with the voltage readings seem like a clear indicator of the likely issue.