DTC P0403: Notes

DTC P0403 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0403	EGR valve (stepper motor) circuit problem
DETECTION CONDITION	California emission regulation applicable ATX model The PCM monitors the EGR valve control signal voltage and current. If the following conditions are met, the PCM determines that there is the EGR control circuit problem. The PCM turns the EGR valve off, but the voltage of the EGR valve control signal remains low. The PCM turns the EGR valve on, but the current of the EGR valve control signal remains high. Diagnostic support note This is a continuous monitor (CCM). The MIL illuminates if the PCM detects the above malfunction conditions in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
DETECTION CONDITION	Except for California emission regulation applicable ATX model The PCM monitors the input voltage from EGR valve. If the voltage remain low or high, the PCM determines that the EGR valve circuit has a malfunction. Diagnostic support note This is a continuous monitor (CCM). The MIL illuminates if the PCM detects the above malfunction conditions in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. FREEZE FRAME DATA is available. Are any DTCs is stored in the PCM memory.
POSSIBLE CAUSE	EGR valve malfunction Connector or terminal malfunction Short to power supply in wiring harness between EGR valve terminal E and PCM terminal 2K Short to power supply in wiring harness between EGR valve terminal A and PCM terminal 2G Short to power supply in wiring harness between EGR valve terminal B and PCM terminal 2L Short to power supply in wiring harness between EGR valve terminal F and PCM terminal 2H Short to ground circuit in wiring harness between EGR valve terminal E and PCM terminal 2K Short to ground circuit in wiring harness between EGR valve terminal A and PCM terminal 2G Short to ground circuit in wiring harness between EGR valve terminal B and PCM terminal 2L Short to ground circuit in wiring harness between EGR valve terminal F and PCM terminal 2H Open circuit in wiring harness between EGR valve terminal E and PCM terminal 2K Open circuit in wiring harness between EGR valve terminal A and PCM terminal 2G Open circuit in wiring harness between EGR valve terminal B and PCM terminal 2L Open circuit in wiring harness between EGR valve terminal F and PCM terminal 2H Open circuit in wiring harness between main relay terminal D and EGR valve terminal C Open circuit in wiring harness between main relay terminal D and EGR valve terminal D PCM malfunction
Courtesy of MAZDA MOTORS CORP.