Inspection Procedure 26: Engine Oil Pressure Switch System

OPERATION

Battery voltage is applied to the engine oil pressure switch 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 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. Perform voltage measurement at engine oil pressure switch connector

Disconnect connector, and measure at the harness side.
Ignition switch: ON
Voltage between terminal engine-ECU OPSW line and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 4.

	Go to Step 2.

STEP 2. Check of short to earth, and open circuit in OPSW line between engine oil pressure switch connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

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

Data list reference table (Refer to ).

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 4. Perform voltage measurement at engine-ECU connector.

Measure engine-ECU terminal voltage.
Engine: Idling
Voltage between terminal OPSW and 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 of damage in OPSW line between engine oil pressure switch connector and engine-ECU connector.

Q. Is the check result normal?

	Replace the engine oil pressure switch.

	Repair the connector(s) or wiring harness.