Q3 Glow Control Unit Failure Causing Multiple Issues

Had the same symptoms on an Audi Q5 2016 diesel last winter. The constant glow plug warning light and engine misfire were clear indicators of a failing glow plug control module. The smoke during acceleration typically happens when one or more glow plugs stop working properly. During the diagnostic test, it turned out two glow plugs were completely dead and the control module had a deteriorated cable connection. The car maintenance involved replacing the faulty control module and all four glow plugs as a preventive measure. A cold start test after the repair confirmed everything was working correctly. This is a serious issue that needs immediate attention since it affects engine performance, fuel efficiency, and can lead to starting problems, especially in cold weather. Running the engine with faulty glow plugs can cause carbon buildup and potential engine damage over time. The repair took about 4 hours in total. The symptoms completely disappeared after fixing both the glow plugs and control module. Would strongly recommend getting it checked soon, as continuing to drive with these symptoms could lead to more expensive repairs.

Thanks for sharing your experience with the glow plug system. My vehicle stalling issues were identical, even the smoke and warning lights matched perfectly. Got it fixed about 3 months ago at a specialized workshop. Really interested to know what you ended up paying for the full repair? My bill seemed steep but not sure if that was normal market price. Also curious if everything has been running smoothly since the fix? No check engine light or cold start problems coming back?

Since getting the glow control unit fixed at the shop, my Audi Q5 has been running perfectly. The heating element system works as intended now, no more vehicle stalling or diesel engine smoke issues. The repair was actually simpler than expected, as the main problem was just a faulty cable connection to the control module, which cost 95 Euro to fix. The diagnostic test revealed no need to replace the glow plugs themselves, which saved quite a bit of money. The engine light hasn't come back on, and cold starts are consistently smooth, even during the coldest mornings. It was definitely worth getting it properly diagnosed and repaired rather than letting it get worse. The specialized workshop did a thorough job testing all components after the repair. Three months later, the fix is still holding up perfectly with no warning lights or starting issues whatsoever.

Thanks everyone for the helpful feedback. After reading about your similar experiences, I finally took my Q3 to a certified diesel specialist last week. The diagnostic confirmed what you all suggested, faulty glow control unit and two bad glow plugs. The total repair came to 480 Euro including parts and labor. They replaced the control unit, installed new glow plugs, and cleaned the connectors. Car maintenance was completed in about 3 hours. The engine light is now off and the vehicle runs like new again. No more smoke during acceleration or cold start problems. Really glad I got it fixed before any serious engine damage occurred. The shop also did a full system check afterward to ensure everything was working properly. The price seemed reasonable considering the parts that needed replacement. Much better experience than my previous mechanic who couldn't properly diagnose the issue.