DTC P0401: EGR System - Insufficient Flow Detected

If DTC P0401 is set, check for a clogged or leaking Exhaust Gas Recirculation (EGR) vacuum line, or a faulty EGR valve. Repair or replace components as necessary. If no problems are found, go to next step.
Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Install SCS Service Check Connector Tool (07PAZ-0010100). See Figure. Test-drive vehicle with no electrical load, with A/T in "D4" position. 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.