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Inspection procedure 27: Engine oil pressure switch system










CIRCUIT OPERATION



COMMENT



TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)



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-119 at engine oil pressure switch and harness connector B-108 at ECM for damage.
note Check harness after checking intermediate connector B-16. If intermediate connector is damaged, repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then confirm that the malfunction symptom is eliminated.

Q. Is the harness connector in good condition?
Go to Step 2.
Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 5.

STEP 2. Measure the power supply voltage at engine oil pressure switch connector B-119.
(1)Disconnect the connector B-119 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?

Go to Step 5.

Go to Step 3.

STEP 3. Check for open circuit or short circuit to ground or harness damage between engine oil pressure switch connector B-119 and ECM connector B-108.
note Check harness after checking intermediate connector B-16. If intermediate connector is damaged, repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then confirm that the malfunction symptom is eliminated.
(1)Disconnect the connector B-119 and B-108 measure at the harness side.

(2)Measure the resistance between connector B-119 (terminal No. 1) and connector B-108 (terminal No. 36).

  • Should be less than 2 Ω.

(3)Check for the continuity between connector B-108 (terminal No. 36) and ground.

  • Not continuity.

Q. Is the harness wire in good condition?

Then go to Step 4.

Repair it. Then confirm that the malfunction symptom is eliminated.

STEP 4. Measure the voltage at ECM connector B-108 by using power plant ECU check harness special tool MB992110.

(1)Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.

(2)Measure the voltage between terminal No. 36 and ground.
OK:
1 V or less (ignition switch: ON)
System voltage (during idling)

Q. Is the measured voltage normal?

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. When the ECM is replaced, register the ID code. Refer to GROUP 42B, Diagnosis - ID Code Registration Judgment Table <Vehicles with KOS> or GROUP 42C, Diagnosis - ID Codes Registration Judgment Table <Vehicles with WCM> .

STEP 5. Measure the voltage at ECM connector B-108 by using power plant ECU check harness special tool MB992110.

(1)Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.

(2)Measure the voltage between terminal No. 36 and ground.
OK:
1 V or less (ignition switch: ON)
10 V or more (during idling)

Q. Is the measured voltage normal?

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