2002 Cadillac DeVille P0171 and P0174 OBD2 Codes - Fuel Quality & Coolant Warning Explanation
I'm currently experiencing only two diagnostic trouble codes: P0171 and P0174. I've already inspected all fuel lines and hoses, and everything appears to be in good condition. Additionally, the dashboard consistently displays a 'Check Coolant Level' message. Despite these checks, the engine performance is affected, and I'm seeking advice on how to resolve this issue.
Have you recently replaced your fuel filter? A dirty or clogged fuel filter could be contributing to the P0171 and P0174 codes. It's worth checking, especially if the engine is running poorly.