EGR Valve: Testing and Inspection

SYMPTOM CHART

DTC P0400 Exhaust gas recirculation flow malfunction.

Possible Source(s):
Insufficient gas flowing in EGR circuit due to a leak
Insufficient gas flowing due to a blocked pipe or stuck valve
Excessive gas flow due to stuck open valve
EGR valve stepper failure
Connector pin(s) bent loose or corroded
ECM failure

Action(s) to take:
GO to Pinpoint Test A.

DTC 0405 Exhaust gas recirculation sensor A circuit low input.

Possible Source(s):
Stepper motor coil open circuit
Harness failure
Connector pin(s) bent or tracking
ECM failure

Action(s) to take:
GO to Pinpoint Test B.

DTC 0406 Exhaust gas recirculation sensor A circuit high input

Possible Source(s):
Stepper motor coil short circuit
Harness short
Connector pin(s) bent or tracking
ECM failure

Action(s) to take:
GO to Pinpoint Test C