P1020
DTC P1020: Mitsubishi Innovative Valve Timing and Lift 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 PCM (terminal No. 27) via the resistor in the PCM.
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 PCM.
- 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 PCM checks whether the engine oil pressure switch turns "OFF" or "ON" during driving.
DTC SET CONDITIONS
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 10 volts or higher.
Judgement Criteria
- Engine speed is 3,000 r/min or lower and engine oil pressure switch is OFF for 2 seconds.
or
- Engine speed is 4,000 r/min or higher and engine oil pressure switch is ON for 2 seconds.
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.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Measure the power supply voltage at PCM connector C-114 by backprobing.
1. Do not disconnect the PCM connector C-114.
2. Start the engine and run at idle.
3. Measure the voltage between terminal No. 27 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 4,000 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. Refer to How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check harness connector B-106 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. Refer to Harness Connector Inspection. Then go to Step 10.
STEP 3. Measure the power supply voltage at engine oil pressure switch connector B-106.
1. Disconnect the connector B-106 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 the voltage normal?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check harness connector C-114 at PCM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 10.
STEP 5. Check for open or shorted circuit to ground between engine oil pressure switch connector B-106 (terminal No. 1) and PCM connector C-114 (terminal No. 27).
Q: Is the harness wire in good condition?
YES: Replace the PCM. Then go to Step 10.
NO: Repair it. Then go to Step 10.
STEP 6. Check harness connector C-114 at PCM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 10.
STEP 7. Check for harness damage between engine oil pressure switch connector B-106 (terminal No. 1) and PCM connector C-114 (terminal No. 27).
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 actuator test item 22: 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 actuator test mode for item 22, Engine oil control valve.
- An operation sound should be heard and vibration should be felt when the evaporative emission purge solenoid is operated.
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. Using scan tool MB991958, read the diagnostic trouble code (DTC).
1. Turn the ignition switch to the "ON" position.
2. Erase the DTC.
3. Warm up the engine until engine coolant temperature reaches 80 °C (176 °F) or higher.
4. What at least 30 seconds since the engine starting sequence was completed, then read the DTC. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P1020 set?
YES: Replace the PCM. Then go to Step 10.
NO: The Inspection is complete.
STEP 10. Using scan tool MB991958, read the diagnostic trouble code (DTC).
1. Turn the ignition switch to the "ON" position.
2. Erase the DTC.
3. Warm up the engine until engine coolant temperature reaches 80 °C (176 °F) or higher.
4. What at least 30 seconds since the engine starting sequence was completed, then read the DTC. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P1020 set?
YES: Retry the troubleshooting.
NO: The Inspection is complete.