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




OPERATION




FUNCTION




TROUBLE JUDGEMENT


Check Conditions
Judgement Criterion

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Check throttle valve control servo relay itself.



  • Throttle valve control servo relay connector check.
  • Throttle valve control servo relay check (Refer to ).

Q. Is the check result normal?

Go to Step 2.
Repair or replace the connector, or replace the throttle valve control servo relay.

STEP 2. Perform voltage measurement at throttle valve control servo relay connector.



  • Remove relay, and measure at relay box side.
  • Voltage between terminal auxiliary battery side power supply line and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 3.

    Repair or replace the connector, or check and repair harness between throttle valve control servo relay connector terminal and auxiliary battery.

    • Check power supply line for open/short circuit.

STEP 3. Perform voltage measurement at throttle valve control servo relay connector.



  • Remove relay, and measure at relay box side.
  • Power supply mode of electric motor switch: ACC
  • Voltage between terminal engine control relay side power supply line and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 4.

    Repair or replace the connector, or check and repair harness between engine control relay connector terminal and throttle valve control servo relay connector terminal.

    • Check power supply line for open/short circuit.

STEP 4. Perform voltage measurement at engine-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Short-circuit engine-ECU connector the terminal C/R to the body earth.
  • Voltage between terminal C/RL and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

    Repair or replace the connector, or check and repair harness between throttle valve control servo relay connector terminal and engine-ECU connector terminal C/RL.

    • Check earthing line for open/short circuit.

STEP 5. Perform voltage measurement at engine-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Short-circuit engine-ECU connector terminals C/R and C/RL to the body earth.
  • Voltage between terminal RSB and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 8.
Go to Step 6.

STEP 6. Check harness between throttle valve control servo relay connector terminal and engine-ECU connector terminal RSB.



  • Check output line for open/short circuit.

Q. Is the check result normal?

Go to Step 7.
Repair or replace the connector, or repair the damaged harness wire.

STEP 7. Check harness between engine control relay connector terminal and throttle valve control servo relay connector terminal.



  • Check power supply line for damage.

Q. Is the check result normal?


    Repair or replace the connector, or check and repair harness between throttle valve control servo relay connector terminal and engine-ECU connector terminal C/RL.

    • Check earthing line for damage.
Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Check harness between throttle valve control servo relay connector terminal and auxiliary battery.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 9.
Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between throttle valve control servo relay connector terminal and engine-ECU connector terminal RSB.



  • Check output line for damage.

Q. Is the check result normal?

Go to Step 10.
Repair or replace the connector, or repair the damaged harness wire.

STEP 10. M.U.T.-III diagnosis code



  • Reconfirmation of diagnosis code.

Q. Is diagnosis code stored?

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