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Exhaust gas recirculation (EGR)

P0403 Exhaust Gas Recirculation (EGR) Control Circuit Malfunction

The ECU monitors the electrical control circuit of the EGR valve or EGR solenoid for open circuits, short circuits and incorrect voltage. P0403 is set when the electrical state of the circuit does not match what the ECU expects.

Common causes

  • Open or shorted wiring to the EGR valve or solenoid
  • Corroded or loose connector
  • Failed EGR valve motor or solenoid coil
  • ECU output driver fault (rare)

Typical symptoms

  • Check engine light (MIL) on
  • EGR valve not operating
  • Rough idle or reduced power on some vehicles
  • Limp mode on some diesel engines

P0403 and NuoVolta

When the EGR valve has been physically removed for off-road or motorsport use, where permitted by law, the NuoVolta EGR Removal solution adjusts the ECU calibration so the valve is no longer controlled, and the DTC removal feature can disable this circuit code. With the valve still fitted, check the wiring and actuator first.

EGR Removal Available for 256 ECUs

Related codes

P0400Exhaust Gas Recirculation (EGR) Flow Malfunction P0401Exhaust Gas Recirculation (EGR) Flow Insufficient Detected P0402Exhaust Gas Recirculation (EGR) Flow Excessive Detected 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.