OBD codes / P0401
P0401
ModerateExhaust Gas Recirculation Flow Insufficient
Get it looked at soon to avoid further wear.
Likely causes
- carbon-clogged EGR passages
- stuck EGR valve
- faulty sensor
Common fixes
- clean EGR valve & passages
- test EGR operation
Seeing P0401 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0401 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.