CIRCUIT OPERATION
- The EGR valve power is supplied from the MFI relay.
- The ECM terminals EGRA, EGRB, EGRC and EGRD drives the stepper motor by sequentially turning "ON" the power transistors in the ECM and providing ground to the EGR valve.
TECHNICAL DESCRIPTION
The ECM checks whether a short circuit to the power supply exists or not by measuring the EGR valve (stepper motor) drive circuit voltage when the current is flowing through the coil of the EGR valve (stepper motor).
DESCRIPTIONS OF MONITOR METHODS
- When the EGR valve (stepper motor) drive circuit voltage is over the specified range, it is judged that a malfunction exists.
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
- Exhaust gas recirculation (EGR) stepper motor monitor
Sensor (The sensor below is determined to be normal)
- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Manifold absolute pressure sensor
Check Condition
- 12V starter battery positive voltage is between 10 and 16.5 volts.
Judgment Criterion
- When EGR valve is energized, the ECM voltage is more than 6.7 volts for 1.4 seconds.
FAIL-SAFE AND BACKUP FUNCTION
OBD-II DRIVE CYCLE PATTERN
- Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- EGR valve (stepper motor) failed.
- Shorted EGR valve (stepper motor) circuit or connector damage.
- ECM failed.