Peugeot 508 Temperature Gauge Issue

Greetings. I am familiar with this issue, though I possess the diesel engine. The symptoms you are experiencing bear a striking resemblance to a problem I encountered with my Peugeot 508. Specifically, the engine's prolonged time to reach its optimal operating temperature, coupled with the illumination of the check engine light, suggests a potential malfunction in the thermal management system. I would ask: have you entertained the notion of a defective fuse? The engine control unit, commonly referred to as the ECU, could be misinterpreting signals from the temperature sensors if the relevant fuse is not functioning correctly.

Thanks for the suggestion. I didn't think about a fuse. Do you know which fuse specifically I should be looking at? And where is it located?

Affirmative. While I cannot ascertain the exact fuse designation without consulting the vehicle's schematic diagram, I strongly advise inspecting the fuse box, typically located within the engine compartment or beneath the dashboard. Delve into the owner's manual for a detailed fuse allocation diagram. Given the symptoms you describe, I recommend prioritizing fuses associated with the engine's cooling system, temperature sensors, and the engine control unit itself. Should the preliminary inspection yield no discernible issues, it might prove prudent to seek the counsel of a qualified automotive technician. This is a cost-effective repair. In my case, the repair cost was approximately 52€. It may be that the fuse is missing and the cooling grille will remain open.

Thanks for the detailed explanation. I'll check the fuses as you suggested. Turns out that it was indeed a defective fuse. Replaced it and everything is back to normal now. Thanks again!