Inspection Procedure 20: Engine 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 engine 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 mark to the combination meter via CAN.
PROBABLE CAUSES
- Failed engine oil pressure switch
- Open/short circuit or harness damage in oil pressure switch circuit or loose connector contact
- Failed engine-ECU
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STEP 1. Voltage measurement at engine oil pressure switch connector (OPSW line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the engine oil pressure switch connector (OPSW line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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 Go to Step 4.
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 Go to Step 2.
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STEP 2. Check of open circuit and short to earth in OPSW line between engine-ECU connector and engine oil pressure switch connector.
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Q.
Is the check result normal?
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Go to Step 3.
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Repair the connector(s) or wiring harness.
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STEP 3. Check the trouble symptoms.
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Q.
Does the trouble symptom persist?
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Replace the engine-ECU.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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STEP 4. Voltage measurement at engine-ECU connector (OPSW terminal).
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(1)Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
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(3)Check the voltage between the engine-ECU connector (OPSW terminal) and body earth.
OK:
1 V or less (ignition switch: ON)
System voltage (during idling)
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Q.
Is the check result normal?
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Go to Step 3.
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Go to Step 5.
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STEP 5. Check of damage in OPSW line between engine-ECU connector and engine oil pressure switch connector.
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Q.
Is the check result normal?
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Replace the engine oil pressure switch.
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Repair the connector(s) or wiring harness.
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