Audi A1 Glow Plug Issues Cause Smoke and CEL

Having worked on a similar issue with my 2011 Audi A3 diesel, I can share my troubleshooting experience. I have some experience with basic car maintenance and electrical issues. The symptoms you describe match what I encountered, persistent glow plug light, check engine warning, and smoke issues. The ignition system showed similar fault patterns, specifically related to the preheating unit connections. My workshop diagnosed it as a faulty cable connection to the heating module. They found corroded contacts in the preheating unit wiring harness. The repair involved cleaning the connections and replacing damaged cables, costing 95 Euro for parts and labor. The smoke during acceleration cleared up completely after the repair, and both warning lights disappeared. The engine also started more smoothly, especially in colder conditions. To provide more specific advice for your case, could you share: Have you scanned for error codes? When did these symptoms first appear? Does the engine take longer to start than usual? Are the issues worse in cold weather? This information would help determine if your defective part shows the same pattern I encountered with my vehicle.

Thanks for sharing your experience. Last service was at 122000 KM with a complete inspection. Just had the car scanned yesterday and error codes point to a defective glow plug control module. The heating module shows intermittent voltage drops according to the diagnostic report. Cold starts are particularly difficult and the car heater takes longer than usual to warm up. The workshop estimates 350 Euro for a complete repair including the replacement of the vehicle heater control unit and connectors. Before proceeding with such a costly fix for these car electronics issues, wanted to confirm if this matches what others paid for similar repairs. Would be helpful to know if your experience with cleaning the connections provided a lasting solution before I commit to replacing the entire control module.

Thanks for the additional details about your A1. Looking back at my A3 repair situation, I should mention that just cleaning the connections only worked temporarily in my case. The issues returned after about 2 months, and I ultimately needed to replace the complete preheating control unit. The 350 Euro quote you received sounds reasonable based on current parts costs. I ended up paying 320 Euro for the complete fix when the cleaning solution failed. The electrical fault kept returning until the entire car preheater module was replaced. Looking at your diagnostic results showing voltage drops, this strongly suggests a failing control unit rather than just dirty connections. The cold start issues and extended heating time match exactly what I experienced before the complete replacement. The fix completely resolved all three issues for me, the persistent glow plug light, engine preheat problems, and the smoke during acceleration. Most importantly, the ignition system now works flawlessly even in cold conditions. From my experience, I would recommend going for the complete replacement rather than trying temporary fixes. The symptoms you describe are nearly identical to what led to my eventual control unit replacement.

Based on this assistance, I appreciate the detailed comparison with your similar repair experience. The pricing matches my expectations and helps confirm the workshop isnt overcharging for the control unit replacement. Your point about temporary fixes eventually failing makes sense. Since the cold start problems and heater performance keep getting worse, I will proceed with the complete 350 Euro repair. The diagnostic results showing voltage drops in the preheating unit match your case exactly, so replacing the entire module seems like the right call versus just cleaning connections. Going to schedule the repair this week and have them replace both the defective part and connectors. Good to know this should resolve all three symptoms, the warning lights, smoke issues, and ignition system problems. Thanks for helping me make an informed decision about the fix.