DTC P0403: Exhaust Gas Recirculation Control Circuit

CIRCUIT OPERATION
• The EGR vacuum regulator solenoid valve power is supplied from the MFI relay (terminal No. 1).
• The PCM controls the EGR vacuum regulator solenoid valve ground by turning the power transistor in the PCM "ON" and "OFF".
TECHNICAL DESCRIPTION
• To judge if there is open circuit in the EGR vacuum regulator solenoid valve drive circuit, PCM measures the surge voltage of the EGR vacuum regulator solenoid valve coil.
DESCRIPTIONS OF MONITOR METHODS
Off-surge does not occur after stepper motor is operated on to off.
MONITOR EXECUTION
Once per driving cycle
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
• Not applicable

Sensor (The sensor below is determined to be normal)
• Not applicable
DTC SET CONDITIONS Logic Flow Chart


Check Conditions
Engine is being cranked.
Battery positive voltage is at between 10 and 16.5 volts.

Judgment Criteria
• The EGR vacuum regulator solenoid valve coil surge voltage (battery positive voltage + 2 volts) is not detected for 0.2 second.
• The PCM monitors for this condition once during the drive cycle.

Check Conditions
Battery positive voltage is at between 10 and 16.5 volts.
ON duty cycle of the EGR vacuum regulator solenoid valve is between 10 and 90 percent.
ON duty cycle of the evaporative emission purge solenoid is 0 percent.
Evaporative emission ventilation solenoid is OFF.
More than 1 second has elapsed after the above mentioned conditions have been met.

Judgment Criteria
• The EGR vacuum regulator solenoid valve coil surge voltage (battery positive voltage + 2 volts) is not detected for 1 second.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor .
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:
• EGR vacuum regulator solenoid valve failed.
• Open or shorted EGR vacuum regulator solenoid valve circuit, harness damage or connector damage.
• PCM failed.