Audi A1 Diesel Glow Plug Issue Causing Rough Idle

I had a very similar issue with my 2014 Audi A3 diesel car. Have some experience with diesel engine maintenance and this specific problem came up last winter. The symptoms matched exactly what youre describing, constant preheating light and rough idle, especially during cold start. The check engine light also came on intermittently. After scanning, it showed a glow plug malfunction. Took it to my regular workshop where they diagnosed a faulty glow plug in cylinder 2. They replaced the defective glow plug and did a full system check to ensure no other components were affected. Total cost was 440 Euro including parts and labor. The repair completely resolved both the warning light and rough idle issues. Before suggesting specific fixes though, could you share: Current mileage on your A1, Whether issues happen more during cold start, If you notice any black smoke from exhaust, Which error code is stored, If fuel consumption has increased This information would help determine if your case is similar and whether there might be related issues to check.

Last service was done at 9500 KM and currently having issues with engine combustion during cold starts. The error code shows P0380 and yes, black smoke appears occasionally during cold start. The engine misfire seems worse in the morning, and fuel efficiency has dropped noticeably in the past weeks. I checked all fuses related to the glow plug system but they appear intact. Your repair experience sounds promising and the cost seems reasonable. My concern is whether replacing just the glow plugs will fix the issue completely or if there could be underlying problems with the preheating system. Did you notice any electrical issues before or after the repair?

Thanks for those additional details. Since fixing my A3's glow plug issue, I can definitely share more relevant experience about the P0380 code and cold start problems. After the glow plug replacement, I had no electrical issues at all. The engine combustion returned to normal, especially during cold starts. The black smoke disappeared completely, which confirmed the problem was indeed tied to the glow plug system. Your symptoms match my experience exactly, the rough cold starts, decreased fuel efficiency, and occasional black smoke are classic signs of glow plug failure in these diesel engines. The P0380 code specifically points to the glow plug circuit, which was the same in my case. One thing to note, while changing the faulty glow plug fixed my issues, the mechanic recommended checking the glow plug control module as well. In my case, it was fine, but its worth having it tested since youre experiencing similar electrical symptoms. The control module test was included in my original 440 Euro repair cost. Looking at your mileage and symptoms, this really sounds like a straightforward glow plug issue rather than a more complex problem with the entire preheating system. The check engine warning should clear once the new glow plugs are installed and the system is reset.

Thanks for the detailed feedback about your A3 repair experience. The matching symptoms with the P0380 code and similar diesel engine issues definitely help confirm my suspicions. I feel more confident now about proceeding with the glow plug replacement. I appreciate the tip about checking the glow plug control module too. Since my fuel efficiency has dropped and the cold start problems are getting worse, I think I'll have both components inspected. The 440 Euro repair cost seems fair for the complete diagnostic and fix. Will schedule the repair soon before the rough idle and check engine warnings potentially lead to bigger problems. Good to know the black smoke and cold start issues should clear up completely once the glow plugs are replaced. This has been really helpful in understanding what to expect from the repair process. Just to confirm, after your repair, did you notice an immediate improvement in cold start performance, or did it take a few days for the engine to run smoothly?