DTC Troubleshooting
DTC Troubleshooting: P0141 (163), P0161 (164)
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 Initial Inspection and Diagnostic Overview.
- 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 systems is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay, and the PCM.
5. Turn the ignition switch to LOCK (0).
6. Check these fuses:
- No. 4 LAF (A/F SENSOR) (15 A) fuse in the driver's under-dash fuse/relay box.
- No. 23 IGP (7.5 A) fuse in the driver's under-dash fuse/ relay box.
Are the fuses OK?
YES -
Go to step 7.
NO -
- If the No. 4 LAF (A/F SENSOR) (15 A) fuse is blown, go to step 22.
- If the No. 23 IGP (7.5 A) fuse is blown, go to step 27.
7. Remove the A/F sensor relay (A) from the driver's under-dash fuse/relay box.
8. Test the A/F sensor relay Testing and Inspection.
Is the relay OK?
YES -
Go to step 9.
NO -
Replace the A/F sensor relay, then go to step 30.
9. Disconnect the secondary HO2S (Sensor 2) 4P connector.
10. At the sensor side, measure the resistance between secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4.
Is there 5.4-7.3 Ohms at room temperature?
YES -
Go to step 11.
NO -
Go to step 29.
11. At the sensor 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 29.
NO -
Go to step 12.
12. Jump the SCS line with the HDS.
13. Disconnect PCM connector C (49P).
14. Check for continuity between PCM connector terminal C5 (C7)* and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PCM (C5 (C7)*) and secondary HO2S (Sensor 2), then go to step 30.
NO -
Go to step 15.
15. Connect secondary HO2S (Sensor 2) 4P connector terminal No. 3 to body ground with a jumper wire.
16. Check for continuity between PCM connector terminals C5 (C7)*and body ground.
Is there continuity?
YES -
Go to step 18.
NO -
Repair an open in the wire between the PCM (C5 (C7)*) and secondary HO2S (Sensor 2), then go to step 30.
17. Connect A/F sensor relay 4P connector terminal No. 2 to body ground with a jumper wire.
18. Check for continuity between secondary HO2S (Sensor 2) 4P connector terminal No. 4 and body ground.
Is there continuity?
YES -
Go to step 19.
NO -
Repair an open in the wire between secondary HO2S (Sensor 2) and the A/F sensor relay, then go to step 30.
19. Disconnect PCM connector A (49P).
20. Connect the A/F sensor relay 4P connector terminal No. 3 to body ground with a jumper wire.
21. Check for continuity between PCM connector terminal A40 and body ground.
Is there continuity?
YES -
Go to step 36.
NO -
Repair an open in the wire between the A/F sensor relay and the PCM (A40), then go to step 30.
22. Remove the A/F sensor relay (A) from the driver's under-dash fuse/relay box.
23. Disconnect the front and rear A/F sensor (Sensor 1) 6P connectors.
24. Disconnect the front and rear secondary HO2S (Sensor 2) 4P connectors.
25. Disconnect the EVAP canister vent shut valve 2P connector.
26. Check for continuity between secondary HO2S (Sensor 2) 4P connector terminal No. 4 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the A/F sensor relay and the secondary HO2S (Sensor 2). If the wire is OK, replace the driver's under-dash fuse/relay box Drivers Under-Dash Fuse/Relay Box (MICU) Removal/Installation. Also replace the No. 4 LAF (A/F SENSOR) (15 A) fuse, then go to step 30.
NO -
Replace the A/F sensor relay. Also replace the No. 23 IGP (7.5 A) fuse, then go to step 30.
27. Remove the A/F sensor relay (A) from the driver's under-dash fuse/relay box.
28. Check for continuity between A/F sensor relay 4P connector terminal No. 4 and body ground.
Is there continuity?
YES -
Replace the driver's under-dash fuse/relay box Drivers Under-Dash Fuse/Relay Box (MICU) Removal/Installation. Also replace the No. 23 IGP (7.5 A) fuse, then go to step 30.
NO -
Replace the A/F sensor relay. Also replace the No. 23 IGP (7.5 A) fuse, then go to step 30.
29. Replace secondary HO2S (Sensor 2) Secondary HO2S Replacement.
30. Reconnect all connectors.
31. Turn the ignition switch to ON (II).
32. Reset the PCM with the HDS.
33. Do the PCM idle learn procedure PCM Idle Learn Procedure.
34. 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, and the PCM, then go to step 1.
NO -
Go to step 35.
35. Monitor the OBD STATUS for DTC P0141 and/or P0161* in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 34, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay, and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.
36. Reconnect all connectors.
37. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
38. Start the engine, and let it idle.
39. 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, and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 38. If the PCM was substituted, go to step 1.
NO -
Go to step 40.
40. Monitor the OBD STATUS for DTC P0141 and/or P0161* in the DTCs MENU with the HDS.
Does the HDS 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 39, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2), the A/F sensor relay, and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 38. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.