OBD codes / P0172
P0172
SeriousSystem Too Rich (Bank 1)
Address promptly — can worsen or affect drivability.
Likely causes
- leaking injector
- bad MAF/O2
- high fuel pressure
- dirty air filter
Common fixes
- check air filter & MAF
- inspect injectors
Seeing P0172 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0172 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.