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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1784 (Engine Controls - Powertrain DTC Charts And Descriptions (Except Diesel & Hybrid)) >> DTC Diagnosis >> P0402 - Exhaust Gas RECIRCULATION (EGR) Flow Excessive Detected

P0402 - Exhaust Gas RECIRCULATION (EGR) Flow Excessive Detected

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2007 Mercury Mountaineer, 2007 Mercury Monterey, 2007 Mercury Montego, 2007 Mercury Milan, and 2007 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
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 (DPFE) 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 differential pressure feedback EGR sensor
  • Damaged differential pressure feedback EGR sensor
  • Incorrect vacuum hose connection
  • Plugged vacuum hoses
  • EVR circuit short 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) - refer to PINPOINT TEST HH . refer to PINPOINT TEST HH .
All others - refer to PINPOINT TEST HE . refer to PINPOINT TEST HE .