P0141
CIRCUIT OPERATION
- Power is supplied from the MFI relay (terminal 1) to the right bank heated oxygen sensor (rear) heater.
- The ECM (terminal 27)
BACKGROUND
- The ECM
DTC SET CONDITIONS
Check Conditions
- Engine coolant temperature is higher than 20 °C (68 °F).
- While the right bank heated oxygen sensor (rear) heater is on.
- Battery positive voltage is at between 11 and 16 volts.
Judgment Criteria
- Heater current of the right bank heated oxygen sensor (rear) heater has continued to be lower than 0.2 ampere or higher than 3.5 ampere for 6 seconds.
- Only one monitor during one drive cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Open or shorted right bank heated oxygen sensor (rear) heater circuit.
- Open circuit in right bank heated oxygen sensor (rear) heater.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools
MB991316: Test Harness
STEP 1. Check connector B-28 at the right bank heated oxygen sensor (rear) for damage.
Q: Is the connector in good condition?
YES: Go to Step 2.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 2. Check the right bank heated oxygen sensor (rear).
1. Disconnect right bank heated oxygen sensor (rear) connector B-28 and connect test harness special tool, MB991316, to the connector on the right bank heated oxygen (rear) sensor side.
2. Measure the resistance between heated oxygen sensor connector terminal 1 (red clip) and terminal 3 (blue clip).
Standard value: 11 - 18 Ohms [at 20 °C (68 °F)]
Q: Is the resistance normal?
YES: Go to Step 3.
NO: Replace the right bank heated oxygen sensor (rear). Then go to Step 12.
STEP 3. Check the power supply voltage at right bank heated oxygen sensor (rear) harness side connector B-28.
1. Disconnect the connector B-28 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 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 5.
NO: Go to Step 4.
STEP 4. Check harness connector A-21X at the MFI relay for damage.
Q: Is the connector in good condition?
YES: Repair harness wire between MFI relay connector A-21X terminal 1 and right bank heated oxygen sensor (rear) connector B-28 terminal 1 because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 5. Check the power supply voltage at ECM connector C-111
1. Do not disconnect the connector C-111
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 27 and ground by backprobing.
- 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 8.
NO: Go to Step 6.
STEP 6. Check connector C-111 at ECM
Q: Is the connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 7. Check for open circuit or short circuit to ground between right bank heated oxygen sensor (rear) connector B-28 terminal 3 and ECM connector C-111 terminal 27
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 8. Check connector C-111 at ECM
Q: Is the connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 9. Check for harness damage between MFI relay connector A-21X terminal 1 and right bank heated oxygen sensor (rear) connector B-28 terminal 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 right bank heated oxygen sensor (rear) connector B-28 terminal 3 and ECM connector C-111 terminal 27
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 a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0141 is output?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points.
STEP 12. Test the OBD-II Drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code(DTC).
Q: Is the DTC P0141 is output?
YES: Retry the troubleshooting.
NO: The inspection is complete.