P0403
DTC P0403: Exhaust Gas Recirculation Control CircuitEGR Valve Circuit Part 1:
EGR Valve Circuit Part 2:
CIRCUIT OPERATION
- The EGR valve power is supplied from the MFI relay (terminal No.4).
- The ECM
TECHNICAL DESCRIPTION
- To judge if there is open circuit in the EGR valve (stepper motor) drive circuit, ECM
DESCRIPTIONS OF MONITOR METHODS
Off-surge does not occur after stepper motor is operated on to off.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- 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
- Throttle position sensor
- Accelerator pedal position sensor
- Manifold absolute pressure sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Battery positive voltage is higher than 10.3 volts.
Judgment Criteria
- The EGR valve motor coil surge voltage (battery positive voltage +2 volts) is not detected for 3 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- EGR valve (stepper motor) failed.
- Open or shorted EGR valve (stepper motor) circuit, or harness damage, or connector damage.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
- MB991658: Test Harness
STEP 1. Check harness connector B-120 at EGR valve for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 2.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 2. Measure the EGR valve motor coil resistance.
1. Disconnect the EGR valve connector B-120.
2. Measure the resistance between EGR valve connector terminal No.2 and either terminal No.1 or terminal No.3.
Standard value: 20 - 24 ohms [at 20°C (68°F)]
3. Measure the resistance between EGR valve connector terminal No.5 and either terminal No.4 or terminal No.6.
Standard value: 20 - 24 ohms [at 20°C (68°F)]
Q: Is the measured resistance between 20 and 24 ohms [at 20°C (68°F)]?
YES: Go to Step 3.
NO: Replace the EGR valve. Then go to Step 12.
STEP 3. Measure the power supply voltage at EGR valve motor harness side connector B-120.
1. Disconnect the connector B-120 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.2, No.5 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 5.
NO: Go to Step 4.
STEP 4. Check harness connector B-12X at MFI relay for damage.
Q: Is the harness connector in good condition?
YES: Repair harness wire between MFI relay connector B-12X (terminal No.4) and idle air control motor connector B-120 (terminal No.2, No.5) because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 5. Measure the power supply voltage at ECM connector C-133
1. Do not disconnect the connector C-133
2. Measure the voltage between terminal (No.3, No.12, No.19, No.26) and ground by backprobing.
- The voltage should be repeat 5 and 8 volts for approximately 3 seconds. When the Ignition switch is turned from the "LOCK" (OFF) position to the "ON" position.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 8.
NO: Go to Step 6.
STEP 6. Check harness connector C-133 at ECM
Q: Is the harness connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 7. Check for open circuit and short circuit to ground between EGR valve connector B-120 and ECM connector C-133
a. EGR valve connector B-120 (terminal No.1) and ECM connector C-133
b. EGR valve connector B-120 (terminal No.3) and ECM connector C-133
c. EGR valve connector B-120 (terminal No.4) and ECM connector C-133
d. EGR valve connector B-120 (terminal No.6) and ECM connector C-133
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 8. Check harness connector C-133 at ECM
Q: Is the harness connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 9. Check the EGR valve operation using special tool MB991658.
1. Remove the EGR valve.
2. Connect special tool MB991658 to the EGR valve. (All terminals should be connected.)
3. Use the jumper wires to connect terminal No.2 of the EGR valve connector to the positive battery terminal.
4. Check to ensure that the motor operates when the terminal No.1 and No.3 of the EGR valve connector are respectively connected to the negative battery terminal using a jumper wire.
- Vibration should be present at each application of voltage to test clip combination.
5. Then, use jumper wires to connect the terminal No. 5 of the EGR valve connector to the positive battery terminal.
6. Check to ensure that the motor operates when terminal No.4 and No.6 of the EGR valve connector are respectively connected to the negative battery terminal using a jumper wire.
- Vibration should be present at each application of voltage to test clip combination.
7. Reinstall the EGR valve, using a new gasket and tighten to the specified torque.
Tighten torque: 24 ±3 N.m [17 ±3 ft.lb]
Q: Is the EGR valve operating properly?
YES: Go to Step 10.
NO: Replace the EGR valve. Then go to Step 12.
STEP 10. Check for harness damage between MFI relay connector B-12X (terminal No.4) and EGR valve connector B-120 (terminal No.2, No.5).
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Check for harness damage between EGR valve connector B-120 and ECM connector C-133
a. EGR valve connector B-120 (terminal No. 1) and ECM connector C-133
b. EGR valve connector B-120 (terminal No. 3) and ECM connector C-133
c. EGR valve connector B-120 (terminal No. 4) and ECM connector C-133
d. EGR valve connector B-120 (terminal No. 6) and ECM connector C-133
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0403 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.