Inspection Procedure 25: Oil Pressure Switch System

OPERATION

Battery voltage is applied to the oil pressure switch connector terminal from the engine-ECU connector terminal OPSW.

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. Perform measurement at oil pressure switch connector

Disconnect connector, and measure at the harness side.
Ignition switch: ON
Voltage between terminal output line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 4.

	Go to Step 2.

STEP 2. Check harness between oil pressure switch connector terminal and engine-ECU connector terminal OPSW.

Check output line for open/short circuit.

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 3. M.U.T.-III data list

Refer to Data List Reference Table .

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 4. Perform voltage measurement at 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 OPSW and body earth.

OK:
1 V or less (ignition switch: ON)
System voltage (during idling)

Q. Is the check result normal?

	Go to Step 3.

	Go to Step 5.

STEP 5. Check harness between oil pressure switch connector terminal and engine-ECU connector terminal OPSW.

Check output line for damage.

Q. Is the check result normal?

	Replace the oil pressure switch.

	Repair or replace the connector, or repair the damaged harness wire.