## DTC Troubleshooting: P0141 (65)

DTC P0141: | Secondary HO2S (Sensor 2) Heater Circuit Malfunction

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 in the DTCs MENU with the HDS. Is DTC P0141 indicated? YES - Go to 5. NO - Intermittent failure, system is OK at this time.Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM.n

5. | Check the No. 3 (7.5 A) fuse in the under-dash fuse/relay box. Is the fuse OK? YES - Go to 6. NO - Repair short in the wire between the secondary HO2S (Sensor 2) and the No. 3 (7.5 A) fuse, then go to 23.

6. | Turn the ignition switch OFF.

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 about 8.1-9.9 W at room temperature? YES - Go to 9. NO - Go to 20.

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 20. NO - Go to 10.

10. | Turn the ignition switch ON (II).

11. | Measure voltage between secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4. Is there battery voltage? YES - Go to 12. NO - Go to 15.

12. | Turn the ignition switch OFF, and wait 10 seconds.

13. | Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

14. | Check for continuity between test pin box terminal No. 125 and body ground. Is there continuity? YES - Repair short in the wire between the ECM connector No. 5 terminal No. 4 (test pin box terminal No. 125) and the secondary HO2S (Sensor 2), then go to 22. NO - Go to 28.

15. | Measure voltage between secondary HO2S (Sensor 2) 4P connector terminal No. 4 and body ground. Is there battery voltage? YES - Go to 16. NO - Repair open in the wire between the secondary HO2S (Sensor 2) and the No. 3 (7.5 A) fuse, then go to 22.

16. | Turn the ignition switch OFF, and wait 10 seconds.

17. | Reconnect the secondary HO2S (Sensor 2) 4P connector.

18. | Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

19. | Measure voltage between test pin box terminals No. 125 and No. 4. Is there 0.1V or less? YES - Repair open in the wire between the ECM connector No. 5 terminal No. 4 (test pin box terminal No. 125) and the secondary HO2S (Sensor 2), then go to 22. NO - Go to 28.

20. | Turn the ignition switch OFF.

21. | Replace the secondary HO2S (Sensor 2).

22. | Reconnect all connectors.

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

24. | Reset the ECM with the HDS.

25. | Do the ETCS learn procedure.

26. | Start the engine.

27. | Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0141 is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Troubleshooting is complete.n

28. | Substitute a known-good ECM.

29. | Start the engine.

30. | Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0141 is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Replace the original ECM.n