DTC P0402: Exhaust Gas RECIRCULATION (EGR) Flow Excessive Detected

P0402 - EXHAUST GAS RECIRCULATION (EGR) FLOW EXCESSIVE DETECTED

Description:	The EGR system is monitored for undesired EGR flow during idle. The EGR monitor looks at the differential pressure feedback EGR (DPFEGR) signal at idle and compares it to the stored signal measured during key on engine off (KOEO). The test fails when the signal at idle is greater than at KOEO by a calibrated amount.
Possible Causes:	EGR valve stuck open Plugged EGR vacuum regulator solenoid vent Plugged EGR tube Slow responding DPFEGR sensor Damaged DPFEGR sensor Incorrect vacuum hose connection Plugged vacuum hoses EGRVR circuit shorted to ground Damaged EGR vacuum regulator solenoid
Diagnostic Aids:	A DPFEGR PID reading that is greater at idle than during KOEO by 0.5 volt or a rough engine idle may indicate a hard fault.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
Vehicles with an EGR system module (ESM)	-	GO to Pinpoint Test HH .	GO to Pinpoint Test HH .
All others	-	GO to Pinpoint Test HE .	GO to Pinpoint Test HE .