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Exhaust gas recirculation (EGR)

P0402 Exhaust Gas Recirculation (EGR) Flow Excessive Detected

The ECU compares actual EGR flow with the commanded value using sensors such as the MAF, MAP or EGR position sensor. P0402 is set when more exhaust gas is recirculated than commanded, typically at idle or when the valve should be closed.

Common causes

  • EGR valve stuck open or not sealing
  • Carbon deposits preventing the valve from closing
  • Faulty EGR position sensor
  • Faulty EGR control solenoid or vacuum supply
  • Wiring or connector faults

Typical symptoms

  • Check engine light (MIL) on
  • Rough or unstable idle and possible stalling
  • Hesitation and poor acceleration
  • Black smoke on diesel engines

P0402 and NuoVolta

If the EGR system has been removed or blanked for off-road or motorsport use, where permitted by law, the NuoVolta EGR Removal solution adjusts the ECU calibration and the DTC removal feature can disable this code. A valve stuck open on a fitted system should be repaired or replaced first.

EGR Removal Available for 256 ECUs

Related codes

P0400Exhaust Gas Recirculation (EGR) Flow Malfunction P0401Exhaust Gas Recirculation (EGR) Flow Insufficient Detected P0403Exhaust Gas Recirculation (EGR) Control Circuit Malfunction P0404Exhaust Gas Recirculation (EGR) Circuit Range/Performance P0405Exhaust Gas Recirculation (EGR) Sensor A Circuit Low P0406Exhaust Gas Recirculation (EGR) Sensor A Circuit High

Diagnose and repair real faults first. Removing or disabling emission systems is only permitted where allowed by law, for example for off-road or motorsport use.