F Pace Diesel Glow Plug Issues & Dark Smoke Fix

Having worked on cars as a hobby for several years, I encountered a similar issue with my 2017 F Type diesel. The vehicle heater system showed identical symptoms, persistent preheating lamp and engine warning light, plus dark exhaust smoke. After inspection, my workshop found a loose electrical connection between the heating module and the main ignition system wiring. The car electronics were basically getting confused by intermittent signals. The repair involved cleaning and reseating the connectors, plus replacing one damaged wire. Total cost was 95€ including diagnostic work. The electrical fault was caught early, preventing damage to the actual preheating elements. Since the fix, the heating system has worked perfectly with no warning lights. Before suggesting specific solutions, could you share: Current mileage, When the symptoms first appeared, Whether the issue happens more during cold starts, If you notice any starting problems, Whether you have access to diagnostic tools This information would help determine if your issue matches what I experienced or points to different components in the preheating system.

Last service completed 2 months ago at 49000 KM. Symptoms match exactly what you described. Cold starts are definitely worse, though starting problems occur out of nowhere regardless of temperature. The engine preheat system seems most affected in damp conditions. Had the car electronics scanned at a local workshop, error code points to the glow plug control module. But wanted to verify if cleaning connections might work before replacing the entire car preheater unit since parts are quite expensive. Currently at 50618 KM, and hoping to resolve this before it potentially causes damage to other components. Would you recommend trying the connection cleaning first or going straight for the control module replacement?

Based on your mileage and symptoms, I would definitely try cleaning the connections first since it solved my identical issue. The electrical fault in my F Type showed the same error code related to the glow plug control module, but the actual preheating unit was perfectly fine. The repair process that worked for me started with a thorough cleaning of all electrical connectors in the heating module area using electrical contact cleaner. Special attention was needed where the preheating control unit connects to the main wiring harness, corrosion often builds up here due to engine heat and moisture. Key areas to check: Main connection points to the heating module, Ground wire connections, Wiring harness near the preheating unit, Glow plug connectors If cleaning resolves the intermittent signals, you will save significantly compared to replacing parts. My total repair cost was under 100€ versus 600€+ for a new control module. However, if cleaning and reseating connections does not fix the issue within a few days, then replacing the preheating control unit would be the next logical step. The damp weather sensitivity you mentioned strongly suggests an electrical connection problem rather than a completely defective part.

Thanks for the detailed suggestions. Your repair experience matches my situation closely, and I will definitely try the electrical connection cleaning approach first. Makes complete sense to check these simpler fixes before investing in expensive components like a new preheating control unit. Will start by having my mechanic thoroughly clean all the connection points you listed, especially around the heating module and preheating unit areas. The damp weather correlation does suggest an electrical issue rather than complete component failure. Really hoping this resolves the persistent preheating lamp and smoke issues without needing major parts replacement. If the cleaning does not work, at least I know the likely next step with the control module. Will plan to get this checked within the week since I want to avoid any potential damage to the ignition system or other engine components. Will update once I know if the connection cleaning solved the problem.