DTC P0401: EGR Insufficient Flow

NOTE: If DTC P1491 is set when DTC P0401 is set, trouble shoot DTC P1491 before trouble shooting DTC P0401.

Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS . Connect SCS service connector. Test drive vehicle and without any electrical load. Decelerate vehicle from 55 MPH for at least 5 seconds. If DTC P0401 is not indicated, problem is intermittent, system is okay at this time. If DTC P0401 is indicated, clean intake manifold EGR port with carburetor cleaner. Clean passage inside EGR valve with carburetor cleaner or replace valve.