DTC Troubleshooting
DTC P0141: Rear Secondary HO2S (Bank 1, Sensor 2) Heater Circuit MalfunctionDTC 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, the system is OK at this time. Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM.
5. Turn the ignition switch OFF.
6. Check these fuses:
- No.19 FI ECU (ECM/PCM) (40 A) fuse in under-hood fuse/relay box.
- No.4 LAF (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, and the fuses, then 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 ohm 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 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 (A8K) and the secondary HO2S (Sensor 2), then go to step 22.
15. Remove the left kick panel, then remove the A/F sensor relay (E) 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 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, then go to step 22.
18. Disconnect ECM/PCM connector A (31P).
19. Check for continuity between ECM/PCM connector terminal E4 and A/F sensor relay 4P connector terminal No. 3.
Is there continuity?
YES - Go to step 20.
NO - Repair open in the wire between the ECM/PCM (E4) and the A/F sensor relay, then go to step 22.
20. Test the A/F sensor relay.
Is the A/F sensor relay OK?
YES - Go to step 28.
NO - Replace the A/F sensor relay, 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 ECM/PCM with the HDS.
25. Do the ECM/PCM idle learn procedure.
26. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0141 and/or P0161* indicated?
YES - Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/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 Temporary DTCs or DTCs were indicated in step 26, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/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 ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
30. Start the engine.
31. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0141 and/or P016V indicated?
YES - Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then recheck. If the ECM/PCM was substituted, go to step 1.
NO - Go to step 32.
32. 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 ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in step 31, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then recheck. If the ECM/PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.