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Inspection Procedure 14: Engine oil pressure switch system
 
 
 
 
CIRCUIT OPERATION
12V battery voltage is applied to the engine oil pressure switch connector terminal number 1 from the ECM connector terminal number 39.
 
 
COMMENT
Detect the engine oil pressure conditions and enter the result into the ECM. 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 ECM sends the command of turning off the oil warning lamp to the combination meter via CAN.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this case:)
  • Engine oil pressure switch failed.
  • Open or shorted engine oil pressure switch circuit, harness damage, or connector damage.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Perform voltage measurement at engine oil pressure switch connector terminal number 1.
  • Disconnect connector, and measure at harness side.
  • Power supply mode of electric motor switch: ON
  • Voltage between engine oil pressure switch connector terminal number 1 and ground.
OK: 12V battery positive voltage
Q: Is the check result normal?
 
2.Step 2. Check of open circuit and short circuit in wiring harness between engine oil pressure switch connector terminal number 1 and ECM connector terminal number 39.
Q: Is the check result normal?
Repair or replace the connector, or repair the damaged harness wire.
 
3.STEP 3. Using scan tool (M.U.T.-III SE), check the data list.
Use scan tool (M.U.T.-III SE) to check the data list (Refer to DATA LIST REFERENCE TABLE).
  • Item number 340: Oil pressure SW
OK:
  • Power supply mode of electric motor switch: ON
  • Engine continuous idling mode : OFF
Q: Is the check result normal?
Replace the engine oil pressure switch (Refer to Engine, Engine Lubrication – Engine oil pressure switch ENGINE OIL PRESSURE SWITCH REMOVAL AND INSTALLATION) Then
 
4.STEP 4. Check of damage in wiring harness between engine oil pressure switch connector terminal number 1 and ECM connector terminal number 39.
Q: Is the check result normal?
Repair or replace the connector, or repair the damaged harness wire.
 
5.STEP 5. Check the malfunction symptoms.
Q: Does the malfunction symptom persist?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
Intermittent malfunction (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
6.STEP 6. Check the malfunction symptoms.
Q: Does the malfunction symptom persist?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
The inspection is complete.