Inspection Procedure 24: Oil Pressure Switch System








OPERATION



  • Battery voltage is applied to the oil pressure switch (terminal No. 1) from the engine-ECU (terminal No. 36).

FUNCTION



  • Detect the oil pressure conditions and enter the result into the engine-ECU. After starting the engine if the oil pressure rises to higher than the given pressure, the oil pressure switch turns OFF. Under this condition the engine-ECU sends the command of turning OFF the oil warning lamp to the combination meter via CAN.

PROBABLE CAUSES



  • Failed oil pressure switch
  • Open/short circuit or harness damage in oil pressure switch circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-13 oil pressure switch connector

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

STEP 2. Perform voltage measurement at B-13 oil pressure switch connector

  • Disconnect connector, and measure at harness 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 3.

STEP 3. Connector check: B-08 engine-ECU connector

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

STEP 4. Check harness between B-13 (terminal No. 1) oil pressure switch connector and B-08 (terminal No. 36) engine-ECU connector.

  • Check output line for open/short circuit.

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

STEP 5. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 90: Oil pressure switch

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

STEP 6. Connector check: B-08 engine-ECU connector

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

STEP 7. Perform voltage measurement at B-08 engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
  • Voltage between terminal No. 36 and earth.
OK:
    1 V or less (ignition switch: ON)
    System voltage (during idling)

Q. Is the check result normal?
Go to Step 5.
Go to Step 8.

STEP 8. Check harness between B-13 (terminal No. 1) oil pressure switch connector and B-08 (terminal No. 36) engine-ECU connector.

  • Check output line for damage.

Q. Is the check result normal?
Replace the oil pressure switch.
Repair the damaged harness wire.