VW Fox Glow Plug Warning Light Stays On After Start

Had a similar situation with my 2012 VW Polo TDI. The glow plug warning light came on and stayed that way, causing cold start problems especially during cooler weather. After diagnostic testing, it turned out two glow plugs were completely defective and one was showing intermittent function. The engine would misfire during cold starts and run rough for the first few minutes. The repair involved replacing all four glow plugs since they tend to wear at similar rates. The issue was fairly serious since bad glow plugs can lead to starting problems and potential engine damage if left unchecked. The diesel car needed proper pre-heating, particularly in cold conditions, to ensure complete fuel combustion. The fix required removing the intake manifold to access all glow plugs. The mechanic also cleaned the glow plug wells and checked the wiring harness for any damage. The entire repair took about 3 hours. Afterward, the engine light cleared and cold starts became smooth again. For a 2009 model with those kilometers, this is fairly common maintenance. Would recommend getting it checked soon to prevent additional engine stress or starting problems.

Thanks for sharing your experience. My Fox had the exact same symptoms with the glow plug warning staying on. Had similar cold start issues and rough idle problems. Got it fixed about 6 months back. Just wondering what the final cost was for your repair? Also curious if youve had any check engine lights or starting troubles since getting the glow plugs replaced? My mechanic mentioned we might need to look at the wiring harness next time.

Thanks for asking about the follow-up. Since getting all glow plugs replaced 6 months ago, my Polo has been running perfectly with no check engine lights or cold start issues. The total repair cost was 440€, which included parts and labor. The rough idle completely disappeared after the fix. The mechanic did a thorough job checking the wiring harness during the repair and found it was actually in good condition. If your mechanic is suggesting a harness inspection, it might be worth checking just to be safe, but I havent needed any additional work since the glow plug replacement. The engine now starts smoothly even in cold weather, and the warning light hasnt returned. These symptoms can definitely make you nervous, but the fix was straightforward once diagnosed properly. Regular maintenance since then has kept everything running well.

Thanks everyone for the helpful replies. Finally got my Fox sorted last week. The mechanic found all four glow plugs were shot and the wiring had some corrosion. Total bill came to 520€ including a new wiring harness. More than I hoped but less than I feared. The shop showed me the old glow plugs, they were completely worn out. No wonder the diesel engine was having trouble with cold starts. The fuel efficiency has actually improved since the repair too. Quick 2-hour job and the warning light cleared right up. Engine combustion is much smoother now, especially during cold starts. Really glad I got it fixed before winter hits. Will definitely keep a closer eye on maintenance intervals going forward. No more warning lights or rough running since the repair. The mechanic did good work explaining everything and showing me the worn parts. Sometimes switching to a new shop works out better than expected.