Audi A4 TDI Startup Issues Point to Faulty Ignition

As someone with basic car repair experience, I had a very similar starting issue with my 2013 Audi A6 TDI. The symptoms you describe match exactly what I encountered, inconsistent starting and rough running when the engine did turn over. After checking my car ignition system, the workshop found a blown fuse that was affecting the ignition coil circuit. The repair was relatively straightforward and cost 52 Euro for parts and labor. The car electronics were thoroughly tested afterward to ensure no other components were affected. However, while my issue was resolved with a simple fuse replacement, starting issues like this can have multiple causes. Before suggesting this might be your specific problem, it would be helpful to know: * Do you hear the fuel pump activate when turning the key? * Are there any error codes showing up? * Does the problem occur more often when the engine is cold or warm? * Have you noticed any other electrical issues? These details would help determine if your problem is similar to what I experienced or if its something else in the ignition system that needs attention.

Thanks for the feedback. I should mention my mileage is 57413 KM and my last service was done 3 months ago. While inspecting the starter motor yesterday, I did notice the fuel pump activates normally when turning the key. No error codes are showing on the dashboard. The starting issue happens more frequently when the engine is cold, especially during the first start of the day. No other electrical issues noticed. Would you still think this points to a simple fuse problem, or should I be looking at other components in the ignition system?

Thanks for providing those additional details. Since we have similar Audi models, I can share more specifics from my experience. While my issue was indeed resolved with a fuse replacement, your symptoms, especially the cold start problems, suggest this might be different from what I encountered. In your case, the normal fuel pump activation and absence of dashboard lights, combined with cold-start issues, points more toward a potential ignition coil problem rather than a simple fuse issue. When my car later developed similar cold-start symptoms, the ignition coil needed replacement, which cost around 180 Euro. The fact that it happens mainly during cold starts is particularly telling. With my A6, I noticed the starting issues were less frequent after the engine warmed up, just like youre describing. The ignition coil becomes less efficient over time, and the symptoms often show up first during cold starts when the system needs more power. Before spending money on parts though, you might want to have the workshop check: * Ignition coil resistance readings * Fuel pressure during cold starts * Crankshaft position sensor output A proper diagnosis with specific readings will help pinpoint whether the ignition coil is actually the culprit or if its another component in the starting system.

Since youve been so helpful with the details, let me update you on the latest. I took your advice and had the workshop check those specific components. They tested the ignition coil resistance and found it was indeed out of spec. They also confirmed the fuel pressure and crankshaft position sensor were working normally. The ignition coil replacement ended up costing 195 Euro, slightly more than what you paid, but the car starts perfectly now, even during cold mornings. The mechanics also cleaned the electrical connections while they were at it, which they said might help prevent similar issues in the future. Really glad I didnt jump straight to replacing the ignition switch, which would have been much more expensive and wouldnt have fixed the actual problem. Thanks for helping narrow down the issue with those specific checks. The car electronics are all working great now, and that frustrating key turn issue is completely resolved.