P0141

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

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine.
4. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0141 and/or P0161* indicated?

YES - Go to step 5.

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

5. Turn the ignition switch OFF.
6. Check these fuses:
- No. 19 OPTION (40 A) fuse in under-hood fuse/relay box.
- No. 4 A/F SENSOR (15 A) fuse in under-dash fuse/relay box.
- No. 23 IGP (7.5 A) fuse in under-dash fuse/relay box.

Are any of the fuses blown?

YES - Repair short in the wire between the A/F sensors, the A/F sensor relay (LAF), and the fuses, then replace the fuse(s), and go to step 22.

NO - Go to step 7.

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




8. At the secondary HO2S (Sensor 2) side, measure 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. 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 the 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 the secondary HO2S (Sensor 2), then go to step 22.




15. Remove the left kick panel (see step 3), then remove the A/F sensor relay (LAF) (A) from the 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 the A/F sensor (Sensor 1) 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. 4.

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).

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 the secondary HO2S (Sensor 2).
22. Reconnect all connectors.
23. Turn the ignition switch ON (II).
24. Reset the PCM with the HDS.
25. Do the PCM idle learn procedure.
26. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated.

YES - If DTC P0141 and/or P0161* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting

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.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM, then go to step 1 If the screen indicates NOT COMPLETED, go to step 25 and recheck

28. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
29. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0141 and/or P0161* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - If the PCM was updated, troubleshooting is complete If the PCM was substituted, replace the original PCM.