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-A/T-ECU (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-A/T-ECU (terminal No. 132).

FUNCTION



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

TROUBLE JUDGMENT


Check Condition
  • Battery voltage is more than 8.3 V.
Judgement Criterion
  • The power line voltage of the electronic controlled throttle system is less than 6.0 V.

PROBABLE CAUSES



  • Open/short circuit in throttle valve control servo circuit or loose connector contact.
  • Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE
note
    *1: L.H.drive vehicles
    *2: R.H.drive vehicles

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*1 or D-137*2, 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 6 .
Go to Step 5 .

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. Connector check: D-212 engine-A/T-ECU connector

Q. Is the check result normal?
Go to Step 7 .
Repair or replace the connector.

STEP 7. Perform voltage measurement at D-212 engine-A/T-ECU 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?
Go to Step 8 .

    Check and repair harness between B-19X (terminal No. 3) throttle valve control servo relay connector and D-212 (terminal No. 15) engine-A/T-ECU connector.

    • Check earthing line for open/short circuit.

STEP 8. Connector check: D-218 engine-A/T-ECU connector

Q. Is the check result normal?
Go to Step 9 .
Repair or replace the connector.

STEP 9. Perform voltage measurement at D-218 engine-A/T-ECU 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 13 .
Go to Step 10 .

STEP 10. Check harness between B-19X (terminal No. 4) throttle valve control servo relay connector and D-218 (terminal No. 132) engine-A/T-ECU connector.

  • Check output line for open/short circuit.

Q. Is the check result normal?
Go to Step 11 .
Repair the damaged harness wire.

STEP 11. Connector check: B-15X engine control relay connector

Q. Is the check result normal?
Go to Step 12 .
Repair or replace the connector.

STEP 12. 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-212 (terminal No. 15) engine-A/T-ECU connector.

    • Check earthing line for open/short circuit.
Repair the damaged harness wire.

STEP 13. 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*1 or D-137*2, and repair if necessary.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 14 .
Repair the damaged harness wire.

STEP 14. Check harness between B-19X (terminal No. 4) throttle valve control servo relay connector and D-218 (terminal No. 132) engine-A/T-ECU connector.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 15 .
Repair the damaged harness wire.

STEP 15. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Replace the engine-A/T-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).