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Inspection procedure 15: Engine oil pressure switch system
 
 
 
 
CIRCUIT OPERATION
  • 12V starter battery voltage is applied to the oil pressure switch from the ECM terminal OPSW.
 
 
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
STEP 1. Measure the power supply voltage at engine oil pressure switch harness side connector.
(1) Disconnect the engine oil pressure switch connector measure at the harness side.
(2) Turn on the power supply mode of the electric motor switch.
(3) Measure the voltage between terminal OPSW and ground.
  • The voltage should equal 12V starter battery positive voltage.
(4) Turn off the power supply mode of the electric motor switch.
Is 12V starter battery positive voltage (approximately 12 volts) present?
Go to Step 4.
Go to Step 2.
 
STEP 2. Check of short to ground and open circuit in OPSW line between ECM connector and engine oil pressure switch connector.
Is the harness wire in good condition?
Go to Step 3.
Repair the connector(s) or wiring harness. Then confirm that the malfunction symptom is eliminated.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check data list item 90: Engine Oil Pressure Switch.
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
(1) Connect scan tool (M.U.T.-IIISE). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-IIISE) .
(2) Turn on the power supply mode of the electric motor switch.
(3) Set scan tool (M.U.T.-IIISE) to the data reading mode for item 90, Engine Oil Pressure Switch.
  • When the engine is stopped, "ON" should be displayed.
  • When the vehicle is continuous idling mode, "OFF" should be displayed.
(4) Turn off the power supply mode of the electric motor switch.
Is the operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/ Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to Removal and Installation ). Then confirm that the malfunction symptom is eliminated.
 
STEP 4. Check of harness damage in OPSW line between ECM connector and engine oil pressure switch connector.
Is the harness wire in good condition?
Replace the engine oil pressure switch. Then confirm that the malfunction symptom is eliminated.
Repair the connector(s) or wiring harness. Then confirm that the malfunction symptom is eliminated.