P1021
DTC P1021: Engine Oil Control Valve CircuitEngine Oil Control Valve Circuit (Part 1):
Engine Oil Control Valve Circuit (Part 2):
CIRCUIT OPERATION
- The engine oil control valve power is supplied from the MFI relay (terminal No. 2).
- The ECM controls ground engine oil control valve by turning the power transistor in the ECM "ON" and "OFF".
TECHNICAL DESCRIPTION
- The engine oil pressure switches the cams to operate the MIVEC system in the low-speed or high-speed mode in accordance with the signals from the ECM.
DESCRIPTIONS OF MONITOR METHODS
Circuit voltage stays low when solenoid status is off.
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)
- Camshaft position sensor
- Mass airflow sensor
- Engine coolant temperature sensor
- Throttle position sensor
- Injection valve
DTC SET CONDITIONS
Logic Flow Chart:
Check Conditions
- Ignition switch: "ON"
- Engine oil control valve is OFF.
- Battery positive voltage is between 10 and 16.5 volts.
- 0.1 seconds has elapsed after the above mentioned conditions have been met.
Judgment Criterion
- The ECM terminal voltage of engine oil control valve circuit is less than 1.5 volts for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to MFI Diagnostic Function -OBD-II Drive Cycle - Pattern 24. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Connector damage.
- Harness damage.
- Engine oil control valve failed.
- 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. Using scan tool MB991958, check data item 98: 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, Oil control valve.
- An operation sound should be heard and vibration should be felt when the engine oil control valve is operated.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the engine oil control valve operating properly?
YES : It can be assumed that this malfunction is intermittent. Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions.
NO : Then go to Step 2.
STEP 2. Check harness connector B-106 engine oil control valve and harness connector B-10 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 3.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 7.
STEP 3. Check the engine oil control valve.
1. Disconnect the engine oil control valve connector B-106.
2. Measure the resistance between engine oil control valve side connector terminal No. 1 and No. 2.
Standard value: 6.9 - 7.9 ohms [at 20 °C (68 °F)]
Q: Is the measured resistance between 6.9 and 7.9 ohms [at 20 °C (68 °F)]?
YES : Go to Step 4.
NO : Replace the engine oil control valve. Then go to Step 7.
STEP 4. Measure the power supply voltage at engine oil control valve harness side 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 battery positive voltage (approximately 12 volts) present?
YES : Go to Step 5.
NO : Repair it because of open circuit or harness damage between relay box (fuse No. 22) and engine oil control valve connector B-106 (terminal No. 1). Then go to Step 7.
STEP 5. Check for open circuit and short circuit to ground and harness damage between engine oil control valve connector B-106 and ECM connector B-10.
1. Disconnect the connector B-106 and B-10 measure at the harness side.
2. Measure the resistance between connector B-106 (terminal No. 2) and connector B-10 (terminal No. 1).
- Should be less than 2 ohms.
3. Check for the continuity between connector B-106 (terminal No. 2) and ground.
- Not continuity.
Q: Is the harness wire in good condition?
YES : Then go to Step 6.
NO : Repair it. Then go to Step 7.
STEP 6. Test the OBD-II Drive Cycle.
1. Carry out test drive with the drive cycle pattern. Refer to MFI Diagnostic Function -OBD-II Drive Cycle-Pattern 24. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q : Is DTC P1021 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Refer to Diagnosis - ID Codes Registration Judgment Table [Vehicles with KOS] or Diagnosis-ID Codes Registration Judgment Table [Vehicles with WCM]. Then go to Step 7.
NO : It can be assumed that this malfunction is intermittent. Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions.
STEP 7. Test the OBD-II Drive Cycle.
1. Carry out test drive with the drive cycle pattern. Refer to MFI Diagnostic Function-OBD-II Drive Cycle-Pattern 24. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q : Is DTC P1021 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.