Inspection Procedure 29: Throttle Position Sensor System








OPERATION



  • A power voltage of 5 V is applied to the electronic-controlled throttle valve (terminal No. 5) from the engine-ECU (terminal No. 76).
  • The power voltage is earthed to the engine-ECU (terminal No. 58) from the electronic-controlled throttle valve (terminal No. 3).
  • The sensor signal is inputted to the engine-ECU (terminal No. 70) from the electronic-controlled throttle valve output terminal (terminal No. 4).

FUNCTION



  • The throttle position sensor converts the throttle valve position into voltage and inputs it into the engine-ECU.
  • The engine-ECU control the throttle valve position.

PROBABLE CAUSES



  • Failed throttle position sensor
  • Open/short circuit or harness damage in throttle position sensor circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-20 electronic-controlled throttle valve connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Perform voltage measurement at B-20 electronic-controlled throttle valve connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 5 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?
Go to Step 6 .
Go to Step 3 .

STEP 3. Connector check: B-17 engine-ECU connector

Q. Is the check result normal?
Go to Step 4 .
Repair or replace the connector.

STEP 4. Check harness between B-20 (terminal No. 5) electronic-controlled throttle valve connector and B-17 (terminal No. 76) engine-ECU.

  • Check power supply line for open/short circuit.

Q. Is the check result normal?
Go to Step 5 .
Repair the damaged harness wire.

STEP 5. Check the trouble symptoms.

Q. Does trouble symptom persist?

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

STEP 6. Connector check: B-17 engine-ECU connector

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

STEP 7. Check harness between B-20 (terminal No. 5) electronic-controlled throttle valve connector and B-17 (terminal No. 76) engine-ECU connector.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 8 .
Repair the damaged harness wire.

STEP 8. Perform resistance measurement at B-20 electronic-controlled throttle valve connector.

  • Disconnect connector, and measure at the harness side.
  • Resistance between terminal No. 3 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?
Go to Step 11 .
Go to Step 9 .

STEP 9. Connector check: B-17 engine-ECU connector

Q. Is the check result normal?
Go to Step 10 .
Repair or replace the connector.

STEP 10. Check harness between B-20 (terminal No. 3) electronic-controlled throttle valve connector and B-17 (terminal No. 58) engine-ECU connector.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?
Go to Step 5 .
Repair the damaged harness wire.

STEP 11. Check harness between B-20 (terminal No. 4) electronic-controlled throttle valve connector and B-17 (terminal No. 70) engine-ECU connector.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 12 .
Repair the damaged harness wire.

STEP 12. Replace the electronic-controlled throttle valve assembly.



  • After replacing the electronic-controlled throttle valve assembly, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Repair the engine-ECU.
The check is end.