Inspection Procedure 23: Engine Oil Pressure Switch System


OPERATION



  • Battery voltage is applied to the engine 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 engine 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 engine oil pressure switch
  • Open/short circuit or harness damage in engine oil pressure switch circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

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

  • Disconnect connector, and measure at the 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-26 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) engine oil pressure switch connector and B-26 (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

  • Data list reference table (Refer to ).

  1. Item 90: Engine 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-26 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-26 engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
  • Engine: Idling
  • 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) engine oil pressure switch connector and B-26 (terminal No. 36) engine-ECU connector.

  • Check output line for damage.

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