P1020
DTC P1020: Mitsubishi Innovative Valve Timing Electronic Control System (MIVEC) Performance ProblemEngine Oil Pressure Switch Circuit:
CIRCUIT OPERATION
- A battery positive voltage is applied to the engine oil pressure switch output terminal (terminal No. 1) from the ECM
TECHNICAL DESCRIPTION
- The engine oil pressure switch converts the existence of a engine oil pressure into a high/low voltage, and inputs it into the ECM
- When the engine oil control valve operates, the engine oil pressure in the MIVEC system rises. The engine oil pressure switch opens, thus interrupting the application of the battery positive voltage. As a result, the output voltage of the engine oil pressure switch will fluctuate between 0 and 12 volts.
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Compare engine oil pressure switch status with engine operating condition.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- 30 seconds or more have passed since the engine starting sequence was completed.
- Engine coolant temperature is 77 °C (171 °F) or higher.
- Battery positive voltage is between 10 and 16.5 volts.
Judgement Criteria
- Engine speed is 3,500 r/min or lower and engine oil pressure switch is OFF for 5 seconds.
or
- Engine speed is 4,500 r/min or higher and engine oil pressure switch is ON for 5 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 19. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are)
- Engine oil pressure switch failed.
- Engine oil control valve failed.
- Open or shorted engine oil pressure switch circuit, harness damage or connector damage.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991923: Power Plant ECU Check Harness
STEP 1. Measure the power supply voltage at ECM
1. Disconnect all ECM
2. Start the engine and run at idle.
3. Measure the voltage between terminal No. 110 and ground.
- Voltage should be 1 volt or less when engine is idling.
- Voltage should be battery positive voltage when engine speed is higher than 4,500 r/min.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage normal?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.
STEP 2. Check harness connector B-33 at engine oil pressure switch for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Then go to Step 10.
STEP 3. Measure the power supply voltage at engine oil pressure switch connector B-33.
1. Disconnect the connector B-33 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 1 and ground.
- Voltage should be 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 6.
NO: Go to Step 4.
STEP 4. Check harness connector B-21 at ECM
Q:
YES: Go to Step 5.
NO: Repair or replace it. Then go to Step 10.
STEP 5. Check for open or shorted circuit to ground between engine oil pressure switch connector B-33 (terminal No. 1) and ECM
Q: Is the harness wire in good condition?
YES: Replace the ECM or the PCM. When the ECM or the PCM is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table. Then go to Step 10.
NO: Repair it. Then go to Step 10.
STEP 6. Check harness connector B-21 at ECM
Q:
YES: Go to Step 7.
NO: Repair or replace it. Then go to Step 10.
STEP 7. Check for harness damage between engine oil pressure switch connector B-33 (terminal No. 1) and ECM
Q: Is the harness wire in good condition?
YES: Go to Step 8.
NO: Repair it. Then go to Step 10.
STEP 8. Using scan tool MB991958, check data list item 98: Engine Oil Control Valve.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 98, Engine oil control valve.
- Warm up the engine. With the engine is idling, the engine oil control valve should be "OFF"
- Warm up the engine. With the engine is 4,500 r/min, the engine oil control valve should be "ON".
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the engine oil control valve operating properly?
YES: Replace the engine oil pressure switch. Then go to Step 9.
NO: Replace the engine oil control valve. Then go to Step 10.
STEP 9. Check the trouble symptoms.
1. Carry out test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 19. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1020 set?
YES: Replace the ECM or the PCM. When the ECM or the PCM is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table. Then go to Step 10.
NO: The Inspection is complete.
STEP 10. Test the OBD-II drive cycle
1. Carry out test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 19. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1020 set?
YES: Retry the trouble shooting.
NO: The Inspection is complete.