P0161

DTC P0141: Rear Secondary HO2S (Bank 1, Sensor 2) Heater Circuit Malfunction (2006 models)

DTC P0161: Rear Secondary HO2S (Bank 2, Sensor 2) Heater Circuit Malfunction (2006 models)

NOTE:
- Information marked with an asterisk (*) applies to the front bank (Bank 2).
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

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 ECM/PCM.

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

Are any of the fuses blown?

YES - Repair short In the wire between the A/F sensors, the secondary HO2S, the A/F sensor relay (LAF), and the fuses, then replace the blown 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 ECM/PCM connector A (31P).




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

Is there continuity?

YES - Repair short in the wire between the ECM/PCM (A9 (A8)*) 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 ECM/PCM connector terminal A9 (A8)* and body ground.

Is there continuity?

YES - Go to step 15.

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




15. Connect secondary HO2S (Sensor 2) 4Pconnector terminal No.4 to body ground with a jumper wire.




16. Remove the A/F sensor relay (LAF) (A).




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, the secondary HO2S, and the A/F sensor relay (LAF), then go to step 22.

18. Disconnect ECM/PCM connector A (31P).




19. Check for continuity between ECM/PCM connector terminal A4 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 ECM/PCM (A4) 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 27.

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

21. Replace the secondary HO2S (Sensor 2).
22. Turn the ignition switch ON (II).
23. Reset the ECM/PCM with the HDS.
24. Do the ECM/PCM idle learn procedure.
25. 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' ECM/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 26.

26. 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 ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 24 and recheck.

27. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
28. 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 ECM/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 ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM.