Q8 Glow Plug Failure Causing Cold Start Issues

Had similar symptoms with my A7 3.0 TDI from 2019. The engine misfire during cold start was the first sign, followed by constant glow plug warning and engine light. Initial diagnosis revealed two faulty glow plugs causing incomplete engine combustion. The repair involved: Full diagnostic scan of the glow plug control module, Removal and testing of all 6 glow plugs, Replacement of 2 defective glow plugs plus control module, System reset and adaptation This was a serious issue requiring immediate attention since faulty glow plugs can lead to starting problems, increased emissions, and potential engine damage if left untreated. The diesel car needed about 4 hours in the shop. After repair, cold start performance improved significantly and all warning lights cleared. The engine now runs smoothly from startup. Would recommend getting this fixed promptly to avoid potential cylinder damage from poor combustion. For reference, all glow plugs should be tested since they typically wear at similar rates. The control module often needs replacement when multiple glow plugs fail.

Totally helped me with my Audi Q8 glow plug issue. The repair worked exactly as described, smooth engine performance now and no more warning lights. The diesel engine starts perfectly even in cold weather. Can you share what the total repair cost was in your case? Also curious if you experienced any other related problems since the fix? My fuel efficiency seems slightly better after the repair.

Since having the glow plug failure fixed at the shop, my diesel car has been running flawlessly. The total repair came to 440 Euro, which covered both the parts and labor. The engine combustion is now perfect with no cold start issues or engine misfire problems. The fix was definitely worth it, as my fuel economy also improved slightly, similar to your experience. The diesel engine now starts instantly and runs smoothly, even in cold conditions. I have not had any related issues in the months since the repair. What really matters is that the glow plug system was properly diagnosed and fixed. Having a proper diagnosis and repair prevents more serious engine damage that could occur from running with faulty glow plugs. My vehicle has performed reliably since the repair with no warning lights or starting problems.

Thanks for all the feedback. I finally got mine fixed last week. Took it to a certified diesel specialist who diagnosed it right away. Like you mentioned, they found faulty glow plugs causing the rough idle and starting issues. The mechanic replaced all glow plugs as a set plus the control module. Total bill came to 520 Euro, bit more than yours but included a full system diagnostic. The engine misfire is completely gone now and cold starts are perfect. No more warning lights on the dash either. Really glad I got it sorted before winter. The diesel engine runs smoother than ever and fuel consumption has definitely improved. Been driving it for a week with zero issues. The specialist mechanic also checked the entire fuel system while it was in, which gave me extra peace of mind.