Cadillac XT4 Glow Plug Warning Light Stays On After Start

A glow plug problem happened on my 2020 XT5 diesel at similar mileage. The check engine light came on first, followed by cold start issues and the permanent glow plug warning. After scanning, it showed multiple glow plug failures. The repair required replacing the entire glow plug set plus the control module. While the engine was still starting, waiting longer would have led to more serious starting problems and potential fuel efficiency issues. The mechanic explained that moisture in the wiring harness had caused corrosion at the connection points. Running a faulty glow plug system can damage other components and increase fuel consumption. It is best to address this promptly. The symptoms match exactly what I experienced, persistent warning light and error codes stored in the system. This is not a typical failure point for these engines at this mileage. Given your previous repair concerns, requesting the diagnostic report and getting a second opinion would be wise. The fix requires specialized diagnostic equipment to properly reset the system after replacement.

Thanks for sharing your experience. I had nearly identical symptoms with my XT4 last winter. The rough idle and starting problems got worse until I had it fixed. I also noticed higher fuel consumption before the repair. Did you remember roughly how much the full repair cost? Just wondering if prices have changed much. Also curious if youve had any engine misfire issues or other problems since getting it fixed. Mine has been running smoothly for about 6 months now but always good to know what to watch out for with these diesel car glow plug systems.

The glow plug replacement on my XT5 diesel car cost 440€ total, including labor and parts. Since getting it fixed, the engine has run perfectly with no misfires or cold start issues. The repair completely resolved the check engine light and warning signals. The mechanic did a thorough job replacing both the glow plugs and control module. Fuel consumption returned to normal immediately after the repair. Looking back, addressing it promptly was definitely the right call to prevent more extensive diesel engine damage. These newer diesel engines are generally very reliable when the glow plug system is functioning correctly. Six months of trouble-free operation sounds about right, once properly repaired, these issues rarely come back. Just keep up with regular maintenance and the system should continue performing well.

Thanks everyone for the advice. After putting it off for a few weeks, I finally took my XT4 to a different mechanic for the glow plug issue. The diagnostic confirmed what you mentioned, failed glow plugs and a faulty control module causing poor engine combustion. The total repair came to 520€, slightly more than expected but worth it. The new shop did great work, properly testing the system after installation. My cold starts are perfect now and the engine light is finally off. Fuel efficiency has improved noticeably too. Best decision was switching mechanics. The new team actually showed me the corroded parts and explained everything. No more engine misfire issues or warning lights since the fix three weeks ago. Really glad I got this sorted before winter.