Glow Plug Control Unit Failure Causing Diesel Smoke

Had the exact same issue with my 2012 Chevy Cruze diesel last winter. The engine misfire and smoke were identical symptoms. After running a diagnostic test, it turned out two glow plugs were completely shot and the wiring harness was corroded, causing poor connections. The heating element in one glow plug had actually fractured, which kept triggering the warning light. The smoke during acceleration was a dead giveaway that the diesel engine wasn't getting proper pre-heating. Originally thought it was just a sensor issue, but it was more serious, the faulty glow plugs were causing incomplete combustion. The repair involved replacing all four glow plugs (since they typically wear at similar rates) and installing a new wiring harness. Would strongly recommend getting this checked soon, running with bad glow plugs can lead to carbon buildup and potential engine damage, especially in cold weather.

Yeah, had almost identical symptoms on my Nubira a while back, those glow plug issues can be really frustrating during cold starts. Your description matches what happened with mine perfectly. My car maintenance guy found two failed glow plugs, plus some wiring problems. Just wondering, how much did the repair end up costing you? And has everything been running smoothly since the fix? Some people told me these issues can sometimes come back if the control module isn't also checked during the repair.

Thanks for asking about the follow-up! After fixing the faulty control unit connection, my Cruze has been running perfectly. The vehicle stalling and smoke issues completely disappeared. The repair was actually much simpler than expected, turned out it was just a loose cable connection to the glow control unit that needed fixing. Total bill came to 95 for the repair, which was way less than I initially feared. The mechanic ran a full diagnostic test afterward to confirm everything was working correctly. The heating element system now works exactly as it should, no more warning lights or cold start problems. It's been about 6 months since the repair, and I haven't had any issues come back. The control unit itself was fine, it was just that damaged connection causing all the trouble. If you're still having problems, definitely get the connections and wiring checked first before replacing more expensive parts. Sometimes these symptoms point to major issues, but it can also be something as simple as a loose connection causing the whole system to act up.

Following up on my initial post, wanted to share how things turned out. Took it to a different mechanic who actually listened to the symptoms. The diagnostic test showed problems with both the glow plugs and control unit. Had all four glow plugs replaced since they were pretty worn. The control unit also needed fixing, turned out there was a corroded connection causing intermittent failures. Whole job cost around 300, but the engine light is finally off and no more smoke during acceleration. The mechanic did a thorough check of the heating element system and found some additional wiring issues that my previous guy missed. Everything's running smooth now, starts perfectly even on cold mornings. Definitely worth getting a second opinion when the first repair attempt doesn't solve the problem. Good call on mentioning the carbon buildup risk, that's actually what convinced me to get it fixed properly instead of just living with it. Amazing what a difference properly functioning glow plugs make to engine performance.