Code No. P0657: Throttle Valve Control Servo Relay Circuit Malfunction

OPERATION

Battery voltage is applied to the throttle valve control servo relay terminal (terminal No. 5).
Battery voltage is applied to the throttle valve control servo relay terminal (terminal No. 1) from the engine control relay (terminal No. 1).
Engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 15) applies current to the throttle valve control servo relay coil by turning ON the power transistor in the unit in order to turn the relay ON.
When the throttle valve control servo relay turns ON, battery voltage is supplied by the throttle valve control servo relay (terminal No. 4) to the engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 132).

FUNCTION

When the ignition switch ON signal is input into the engine-ECU <M/T> or engine-A/T-ECU <A/T>, the engine-ECU <M/T> or engine-A/T-ECU <A/T> turns ON the Throttle valve control servo.

TROUBLE JUDGMENT

Check Condition

Battery positive voltage is 8.3 V or higher.

Judgement Criterion

The power line voltage of the electronic controlled throttle system is 6.0 V or less.

PROBABLE CAUSES

Failed throttle valve return spring
Open/short circuit in throttle valve control servo circuit or loose connector contact.
Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS

STEP 1. Connector check: B-19X throttle valve control servo relay connector

Q. Is the check result normal?

	Go to Step 2 .

	Repair or replace the connector.

STEP 2. Check throttle valve control servo relay itself.

Check throttle valve control servo relay itself (Refer to ).

Q. Is the check result normal?

	Go to Step 3 .

	Replace the throttle valve control servo relay.

STEP 3. Perform voltage measurement at B-19X throttle valve control servo relay connector.

Remove relay, and measure at relay box side.
Voltage between terminal No. 5 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 4 .

	Check intermediate connector A-03 <L. H. drive vehicles> or D-137 <R. H. drive vehicles>, and repair if necessary. If intermediate connector is normal, check and repair harness between B-19X (terminal No. 5) throttle valve control servo relay connector and battery. Check power supply line for open/short circuit.

STEP 4. Perform voltage measurement at B-19X throttle valve control servo relay connector.

Remove relay, and measure at relay box side.
Ignition switch: ON
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 5 .

	Go to Step 6 .

STEP 5. Connector check: B-15X engine control relay connector

Q. Is the check result normal?

	Check and repair harness between B-15X (terminal No. 1) engine control relay connector and B-19X (terminal No. 1) throttle valve control servo relay connector. Check power supply line for open/short circuit.

	Repair or replace the connector.

STEP 6. Perform voltage measurement at D-243 engine-ECU <M/T> connector or D-212 engine-A/T-ECU <A/T> connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 15 and earth.

OK: System voltage

Q. Is the check result normal?

	Check and repair harness between B-19X (terminal No. 3) throttle valve control servo relay connector and D-243 (terminal No. 15) engine-ECU <M/T> connector or D-212 (terminal No. 15) engine-A/T-ECU <A/T> connector. Check earthing line for open/short circuit.

	Go to Step 7 .

STEP 7. Perform voltage measurement at D-247 engine-ECU <M/T> connector or D-218 engine-A/T-ECU <A/T> connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 132 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 10 .

	Go to Step 8 .

STEP 8. Check harness between B-19X (terminal No. 4) throttle valve control servo relay connector and D-247 (terminal No. 132) engine-ECU <M/T> connector or D-218 (terminal No. 132) engine-A/T-ECU <A/T> connector.

Check output line for open/short circuit.

Q. Is the check result normal?

	Go to Step 9 .

	Repair the damaged harness wire.

STEP 9. Check harness between B-15X (terminal No. 1) engine control relay connector and B-19X (terminal No. 1) throttle valve control servo relay connector.

Check output line for damage.

Q. Is the check result normal?

	Check and repair harness between B-19X (terminal No. 3) throttle valve control servo relay connector and D-243 (terminal No. 15) engine-ECU <M/T> connector or D-212 (terminal No. 15) engine-A/T-ECU <A/T> connector. Check earthing line for open/short circuit.

	Repair the damaged harness wire.

STEP 10. Connector check: D-243 and D-247 engine-ECU <M/T> connector or D-212 and D-218 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

	Go to Step 11 .

	Repair or replace the connector.

STEP 11. Check harness between B-19X (terminal No. 5) throttle valve control servo relay connector and battery.

note

Before checking harness, check intermediate connector A-03 <L. H. drive vehicles> or D-137 <R. H. drive vehicles>, and repair if necessary.

Check power supply line for damage.

Q. Is the harness connector in good condition?

	Go to Step 12 .

	Repair the damaged harness wire.

STEP 12. Check harness between B-19X (terminal No. 4) throttle valve control servo relay connector and D-247 (terminal No. 132) engine-ECU <M/T> connector or D-218 (terminal No. 132) engine-A/T-ECU <A/T> connector.

Check power supply line for damage.

Q. Is the harness connector in good condition?

	Go to Step 13 .

	Repair the damaged harness wire.

STEP 13. Check the trouble symptoms.

Q. Does trouble symptom persist?

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).