P1021
DTC P1021: Oil Feeder Control Valve CircuitOil Feeder Control Valve Circuit Part 1:
Oil Feeder Control Valve Circuit Part 2:
CIRCUIT OPERATION
- The oil feeder control valve power is supplied from the MFI relay (terminal No.4).
- The ECM controls ground oil feeder control valve by turning the power transistor in the ECM "ON" and "OFF".
TECHNICAL DESCRIPTION
- The oil feeder control valve 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
Oil feeder control valve circuit voltage is less than specified value.
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
- Ignition switch: ON
- Oil feeder control valve is "OFF".
- Battery positive voltage is between 10 and 16.5 volts.
- 0.1 second has elapsed after the above mentioned conditions have been met.
Judgment Criterion
- The ECM terminal voltage of oil feeder control valve circuit is less than 1.5 volts for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Oil feeder control valve failed.
- Open or shorted oil feeder control valve circuit, or 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
- MB991911: Main Harness B
STEP 1. Check harness connector B-124 at the oil feeder control valve for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 2.
NO: Repair or replace it. Then go to Step 12.
STEP 2. Check the oil feeder control valve.
1. Disconnect the oil feeder control valve connector B-124.
2. Measure the resistance between oil feeder control valve side connector terminal No.1 and No.2.
Standard value: 6.9 - 7.9 Ohms [at 20 degrees C (68 degrees F)]
Q: Is the measured resistance between 6.9 and 7.9 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 3.
NO: Replace the oil feeder control valve. Then go to Step 12.
STEP 3. Measure the power supply voltage at oil feeder control valve harness side connector B-124.
1. Disconnect the connector B-124 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: Go to Step 4.
STEP 4. Check harness connector B-12X at MFI relay for damage.
Q: Is the harness connector in good condition?
YES: Check harness connector C-105 at intermediate connector for damage, and repair or replace as required. If intermediate connector is in good condition, repair harness wire between MFI relay connector B-12X (terminal No.4) and oil feeder control valve connector B-124 (terminal No.1) because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Then go to Step 12.
STEP 5. Measure the power supply voltage at ECM connector C-121 by backprobing.
1. Do not disconnect the connector C-121.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.32 and ground by backprobing.
- 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 8.
NO: Go to Step 6.
STEP 6. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Then go to Step 12.
STEP 7. Check for open circuit and short circuit to ground between oil feeder control valve connector B-124 (terminal No.2) and ECM connector C-121 (terminal No.32).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 8. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Then go to Step 12.
STEP 9. Check for harness damage between MFI relay connector B-12X (terminal No.4) and oil feeder control valve connector B-124 (terminal No.1).
Q: Is the harness wire in good condition?
YES: Go to Step 10.
NO: Repair it. Then go to Step 12.
STEP 10. Check for harness damage between oil feeder control valve connector B-124 (terminal No.2) and ECM connector C-121 (terminal No.32).
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Check the trouble symptoms.
1. Carry out test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1021 set?
YES: Replace the ECM. Then go to Step 12.
NO: It can be assumed that this malfunction is intermittent.
STEP 12. 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 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1021 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.