Inspection Procedure 9: Crank Angle Sensor System










OPERATION



  • Power is supplied to the crank angle sensor (terminal No. 3) from the engine-ECU (terminal No. 27) and is earthed to the engine-ECU (terminal No. 12) from the crank angle sensor (terminal No. 1).
  • A power voltage of 5 V is applied to the crank angle sensor output terminal (terminal No. 2) from the engine-ECU (terminal No. 13).

FUNCTION



  • The crank angle sensor detects the crank angle (position) and inputs a pulse signal to the engine-ECU.
  • In response to the signal, the engine-ECU controls the injector, etc.

PROBABLE CAUSES



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

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-30 intermediate connector

Q. Is the check result normal?

Go to Step 2 .
Repair or replace the connector.

STEP 2. Perform voltage measurement at B-30 intermediate connector.

  • Disconnect connector, and measure at the female side.
  • Ignition switch: ON
  • Voltage between terminal No. 12 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 8 .
Go to Step 3 .

STEP 3. Perform voltage measurement at B-27 engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992044) to measure at connector for inspection.
  • Disconnect B-30 intermediate connector.
  • Ignition switch: ON
  • Voltage between terminal No. 13 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 4 .
Go to Step 5 .

STEP 4. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?


    Check and repair harness between B-30 (terminal No. 12) intermediate connector and B-27 (terminal No. 13) engine-ECU connector.

    • Check output line for open circuit.
Repair or replace the connector.

STEP 5. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?

Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between B-30 (terminal No. 12) intermediate connector and B-27 (terminal No. 13) engine-ECU connector.

  • Check output line for short circuit.

Q. Is the check result normal?

Go to Step 7 .
Repair or replace the connector.

STEP 7. 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 8. Perform voltage measurement at B-30 intermediate connector.

  • Disconnect connector, and measure at the female side.
  • Ignition switch: ON
  • Voltage between terminal No. 6 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 11 .
Go to Step 9 .

STEP 9. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?

Go to Step 10 .
Repair or replace the connector.

STEP 10. Check harness between B-30 (terminal No. 6) intermediate connector and B-27 (terminal No. 27) engine-ECU connector.

  • Check power supply line for open/short circuit.

Q. Is the check result normal?

Go to Step 7 .
Repair the damaged harness wire.

STEP 11. Perform resistance measurement at B-30 intermediate connector.

  • Disconnect connector, and measure at the female side.
  • Resistance between terminal No. 5 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 14 .
Go to Step 12 .

STEP 12. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?

Go to Step 13 .
Repair or replace the connector.

STEP 13. Check harness between B-30 (terminal No. 5) intermediate connector and B-27 (terminal No. 12) engine-ECU connector.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?

Go to Step 7 .
Repair the damaged harness wire.

STEP 14. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?

Go to Step 15 .
Repair or replace the connector.

STEP 15. Check harness between B-30 (terminal No. 6) intermediate connector and B-27 (terminal No. 27) engine-ECU connector.

  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 16 .
Repair the damaged harness wire.

STEP 16. Check harness between B-30 (terminal No. 12) intermediate connector and B-27 (terminal No. 13) engine-ECU connector.

  • Check output line for damage.

Q. Is the check result normal?

Go to Step 17 .
Repair the damaged harness wire.

STEP 17. Check harness between B-30 (terminal No. 12) intermediate connector and B-30-2 (terminal No. 2) crank angle sensor connector.

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

Q. Is the check result normal?

Go to Step 18 .
Repair the damaged harness wire.

STEP 18. Check harness between B-30 (terminal No. 5) intermediate connector and B-30-2 (terminal No. 1) crank angle sensor connector.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?

Go to Step 19 .
Repair the damaged harness wire.

STEP 19. Check harness between B-30 (terminal No. 6) intermediate connector and B-30-2 (terminal No. 3) crank angle sensor connector.

  • Check power supply line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 20 .
Repair the damaged harness wire.

STEP 20. Check the sensor wheel.

Q. Is the check result normal?

Go to Step 21 .
Replace the sensor wheel.

STEP 21. Replace the Crank angle sensor.

  • After replacing the crank angle sensor, re-check the trouble symptom.

Q. Does trouble symptom persist?

Replace the engine-ECU.
The check is end.