DTC Troubleshooting

DTC Troubleshooting: P0141, P0161

DTC P0141: Rear Secondary HO2S (Bank 1, Sensor 2) Heater Circuit Malfunction

DTC P0161: Front Secondary HO2S (Bank 2, Sensor 2) Heater Circuit Malfunction

NOTE:

- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes

- Information marked with an asterisk (*) applies to the front bank (Bank 2).

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS.

3. Start the engine.

4. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0141 and/or P0161* indicated?
YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM.


5. Turn the ignition switch to LOCK (0).

6. Check the No. 4 A/F SENSOR (15 A) fuse in the driver's under-dash fuse/relay box.

Is the fuse OK?
YES - Go to step 7.

NO - Repair short in the wire between the front A/F sensor, the rear A/F sensor, the front secondary HO2S, the rear secondary HO2S, the EVAP canister vent shut valve, the A/F sensor relay, and the fuse, then replace the blown fuse, and go to step 23.


7. Disconnect the secondary HO2S (Sensor 2) 4P connector.

8. At the secondary HO2S (Sensor 2) side, measure the resistance between secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4.

Is there 5.4-6.6 Ohms at room temperature?
YES - Go to step 9.

NO - Go to step 21.






9. At the secondary HO2S (Sensor 2) side, check for continuity between body ground and secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4 individually.

Is there continuity?
YES - Go to step 21.

NO - Go to step 10.






10. Jump the SCS line with the HDS.

11. Disconnect PCM connector A (31P).

12. Check for continuity between PCM connector terminal A9 (A8)* and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (E9 (E8)*) and secondary HO2S (Sensor 2), then go to step 22.

NO - Go to step 13.






13. Connect secondary HO2S (Sensor 2) 4P connector terminal No. 3 to body ground with a jumper wire.






14. Check for continuity between PCM connector terminal A9 (A8)* and body ground.

Is there continuity?
YES - Go to step 15.

NO - Repair open in the wire between the PCM (A9 (A8)*) and secondary HO2S (Sensor 2), then go to step 22.






15. Remove the left kick panel, Interior Trim Removal/Installation - Front Door Sill Area then remove the A/F sensor relay (LAF) (A) from the driver's under-dash fuse/relay box.






16. Connect secondary HO2S (Sensor 2) 4P connector terminal No. 4 to body ground with a jumper wire.






17. Check for continuity between A/F sensor relay (LAF) 4P connector terminal No. 2 and body ground.

Is there continuity?
YES - Go to step 18.

NO - Repair open in the wire between secondary HO2S (Sensor 2) and the A/F sensor relay (LAF), then go to step 22.






18. Disconnect PCM connector E (31P).

19. Check for continuity between PCM connector terminal E4 and A/F sensor relay (LAF) 4P connector terminal No. 3.

Is there continuity?
YES - Go to step 20.

NO - Repair open in the wire between the PCM (E4) and the A/F sensor relay (LAF), then go to step 22.






20. Test the A/F sensor relay (LAF). Power Relay Test

Is the A/F sensor relay (LAF) OK?
YES - Go to step 28.

NO - Replace the A/F sensor relay (LAF), then go to step 22.


21. Replace secondary HO2S (Sensor 2). Secondary HO2S Replacement

22. Reconnect all connectors.

23. Turn the ignition switch to ON (II).

24. Reset the PCM with the HDS.

25. Do the PCM idle learn procedure. PCM Idle Learn Procedure

26. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0141 and/or P0161* indicated?
YES - Check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM, then go to step 1.

NO - Go to step 27.


27. Monitor the OBD STATUS for DTC P0141 and/or P0161* in the DTCs MENU with the HDS.

Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 26, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.


28. Reconnect all connectors.

29. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Reading and Clearing Diagnostic Trouble Codes

30. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0141 and/or P0161* indicated?
YES - Check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 31.


31. Monitor the OBD STATUS for DTC P0141 and/or P0161* in the DTCs MENU with the HDS.

Does the screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Pending or Confirmed DTCs were indicated in step 30, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.