DTC P0401: EGR System - Insufficient Flow Detected
- Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Connect scan tool. Test drive vehicle with no electrical load. Decelerate gradually from 55 MPH for at least 5 seconds. If DTC P0401 resets, go to next step. If DTC P0401 does not reset, problem is intermittent. System is okay at this time.
- Clean intake manifold EGR port and EGR passage with carburetor cleaner. Clean passage inside EGR valve with carburetor cleaner, or replace EGR valve as necessary.