RS7 Cranking Issue: Dead Starter Likely Culprit

Had the same problem on my 2016 S7 last month. The symptoms match exactly, multiple error codes, clicking sound, electronics working but no turnover. The issue traced back to a combination of problems in the electrical system. The main culprit was corrosion at the battery terminals causing a voltage drop, despite appearing normal. The secondary issue was a faulty relay switch in the fuse box controlling the starter circuit. The repair involved: Cleaning and replacing battery terminals, Testing the wiring harness for continuity, Replacing the starter relay switch, Reprogramming the ECU to clear persistent codes This was a serious electrical system issue that could have damaged other components if left unaddressed. The starter motor and ignition switch tested fine, confirming the problem was in the power delivery path rather than the mechanical components. Before heading to the shop, check the battery terminals for any visible corrosion or loose connections. A proper diagnosis requires professional testing equipment to measure voltage drops across the charging circuit.

Thank you for the detailed response on this starter issue. The symptoms and repair steps you described match my situation perfectly. My car won't start with the same clicking sound, and your explanation about the voltage drop makes sense. Quick follow up, what was your total repair cost for fixing the starter solenoid and electrical issues? Also curious if youve had any similar problems since the repair? Just want to get an idea of whether this might be a recurring issue before I tackle the repairs.

Had the RS7 checked by the mechanic yesterday and got everything sorted. The main problem was indeed the Terminal 15 ignition positive being interrupted, just as suspected. The circuit break was caused by a loose connection that was affecting the starter solenoid. The repair was straightforward, they fixed the cable connection that was causing the power supply interruption. Total cost came to 95 Euro, which was honestly less than expected given the initial symptoms. Since the fix, the car starts perfectly every time. No clicking sounds, no error codes, and the power delivery to the starter is consistent. Its been about two weeks of daily driving with zero issues. The mechanic mentioned this type of problem rarely recurs if properly repaired, as it was mainly due to a physical connection fault rather than an electronic component failure. If your car wont start with similar symptoms, its worth having the ignition circuit checked first before replacing any major components. Often these electrical gremlins come down to simple connection issues rather than failed parts.

Here is my experience resolving the starting issue: Finally got the RS7 back from the shop today. They found exactly what you described, corroded battery terminals and a faulty relay in the fuse box were preventing proper power flow to the starter solenoid. The mechanic showed me the crusty battery connections, which looked fine on the surface but had corrosion underneath. They cleaned both terminals, replaced the main starter relay, and tested all the connections in the power supply circuit. Total repair came to 280 Euro, including parts and labor. More than I hoped but less than I feared. The starter and ignition switch were perfectly fine as you suggested. Car starts instantly now with no clicking or error codes. The shop said this kind of electrical issue is pretty common but shouldn't recur if properly fixed. Really glad I had them check the simple stuff first instead of replacing major components unnecessarily. Thanks again for pointing me in the right direction on this one. Saved me from potentially much bigger headaches and costs.