STEP 1. Check the throttle actuator control motor relay.
STEP 2. Measure the power supply voltage at throttle actuator control motor relay harness side connector.
(1) Remove the throttle actuator control motor relay and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal switch power supply line and ground.- Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 3. Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in switch power supply line between MFI relay connector and throttle actuator control motor relay connector. Then go to Step 11.
STEP 3. Measure the power supply voltage at throttle actuator control motor relay harness side connector.
(1) Remove the throttle actuator control motor relay and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal coil power supply line and ground.- Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 4. Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in coil power supply line between MFI relay connector and throttle actuator control motor relay connector. Then go to Step 11.
STEP 4. Measure the power supply voltage at ECM harness side connector.
(1) Disconnect the ECM connector and measure at the harness side.
(2) Short-circuit the terminal C/R of the ECM harness connector to the ground.
(3) Measure the voltage between terminal C/RL and ground.- Voltage should be battery positive voltage.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 5. Repair or replace the connector(s), or check and repair the harness of short to ground and open circuit in C/RL line between throttle actuator control motor relay connector and ECM connector. Then go to Step 11.
STEP 5. Measure the power supply voltage at ECM harness side connector.
(1) Disconnect the ECM connector and measure at the harness side.
(2) Short-circuit the terminals C/R and C/RL of the ECM harness connector to the ground.
(3) Measure the voltage between terminal RSB and ground.- Voltage should be battery positive voltage.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 8. Go to Step 6.
STEP 6. Check of short to ground and open circuit in RSB line between throttle actuator control motor relay connector and ECM connector.
STEP 7. Check of harness damage in coil power supply line between MFI relay connector and throttle actuator control motor relay connector.
STEP 8. Check of harness damage in switch power supply line between MFI relay connector and throttle actuator control motor relay connector.
STEP 9. Check of harness damage in RSB line between throttle actuator control motor relay connector and ECM connector.
STEP 10. Check the trouble symptoms.
STEP 11. 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 - Pattern 1 . (2) Check the diagnostic trouble code (DTC).
Is DTC P0657 set?
Retry the troubleshooting. The inspection is complete.