Inspection Procedure 28

Inspection procedure 28: Engine oil pressure switch system

Engine Oil Pressure Switch Circuit:

CIRCUIT OPERATION
- Battery voltage is applied to the oil pressure switch (terminal No. 1) from the engine-ECU (terminal No. 36).

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 code to be set are:)
- Engine oil pressure switch failed.
- Open or shorted engine oil pressure switch circuit, harness damage, or connector damage.
- ECM failed.

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Check harness connector B-15 at engine oil pressure switch for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 2.

NO : Repair or replace it. Then go to Step 5.

STEP 2. Measure the power supply voltage at engine oil pressure switch connector B-15.

1. Disconnect the connector B-15 measure at the harness side.
2. Turn the ignition switch to the "ON" position.







3. Measure the voltage between terminal No. 1 and ground.
- The voltage should equal battery positive voltage.

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is battery positive voltage (approximately 12 volts) present?

YES : Go to Step 5.

NO : Go to Step 3.

STEP 3. Check harness connector B-09 ECM connector for damage.

Q: Is the connector in good condition?

YES : Go to Step 4.

NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 4. Check for open circuit and short circuit to ground between ECM connector B-09 (terminal No. 36) and engine oil pressure switch connector B-15 (terminal No. 1)

Q: Is the harness wire in good condition?

YES : Replace the ECM. When the ECM is replaced, register the ID code. Then confirm that the malfunction symptom is eliminated.

NO : Repair it. Then confirm that the malfunction symptom is eliminated.

STEP 5. Check harness connector B-09 ECM connector for damage.

Q: Is the connector in good condition?

YES : Go to Step 6.

NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 6. Check for harness damage between ECM connector B-09 (terminal No. 36) and engine oil pressure switch connector B-15 (terminal No. 1)

Q: Is the harness wire in good condition?

YES : Replace the engine oil pressure switch. Then confirm that the malfunction symptom is eliminated.

NO : Repair it. Then confirm that the malfunction symptom is eliminated.