Inspection Procedure 27

Inspection procedure 27: Engine oil pressure switch system














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-16 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. Harness Connector Inspection.
Then go to Step 5 .
STEP 2. Measure the power supply voltage at engine oil pressure switch connector B-16.

(1)Disconnect the connector B-16 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-10 ECM connector for damage.

Q. Is the connector in good condition?

YES Go to Step 4.
NO Repair or replace it. Harness Connector Inspection.
Then confirm that the malfunction symptom is eliminated.
STEP 4. Check for open circuit and short circuit to ground between ECM connector B-10 (terminal No. 36) and engine oil pressure switch connector B-16 (terminal No. 1)

NOTE:
Check harness after checking intermediate connector B-24. If intermediate connector is damaged, repair or replace it. After to Harness Connector Inspection Harness Connector Inspection.
Then check that the malfunction is eliminated.

Q. Is the harness wire in good condition?

YES Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID registration procedure manual - ID codes registration judgement table [Vehicles with KOS] or ID registration procedure manual - ID codes registration judgement table [Vehicles with WCM]. 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-10 ECM connector for damage.

Q. Is the connector in good condition?

YES Go to Step 6.
NO Repair or replace it. Harness Connector Inspection.
Then confirm that the malfunction symptom is eliminated.
STEP 6. Check for harness damage between ECM connector B-10 (terminal No. 36) and engine oil pressure switch connector B-16 (terminal No. 1)

NOTE:
Check harness after checking intermediate connector B-24. If intermediate connector is damaged, repair or replace it. After to Harness Connector Inspection Harness Connector Inspection.
Then check that the malfunction is eliminated.

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.