P0139

DTC P0139: Secondary HO2S (Sensor 2) Circuit Slow Response

NOTE: Information marked with asterisk (*) applies to M/T model.

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
4. Test-drive under these conditions:

- Engine coolant temperature more than 158°F (70°C)
- A/T in D position (M/T in 4th gear)
- Engine speed at 1,400 - 2,500 (2,000 - 3,000)* rpm
- Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

5. Monitor the OBD STATUS for DTC P0139 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?

YES - Go to step 6.

NO - If the screen indicates PASSED, intermittent failure, system is OK at this time. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 3 and recheck.

6. Turn the ignition switch OFF.
7. Replace the secondary HO2S (Sensor 21).
8. Turn the ignition switch ON (II).
9. Reset the ECM/PCM with the HDS.
10. Do the ECM/PCM idle learn procedure.
11. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
12. Test-drive under these conditions:


- Engine coolant temperature more than 158°F (70°C)
- A/T in D position (M/T in 4th gear)
- Engine speed at 1,400 - 2,500 (2,000 - 3,000)* rpm
- Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

13. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC PO139 is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) 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 14.

14. Monitor the OBD STATUS for DTC P0139 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) and the ECM/PCM, then go to step 1. If the screen indicates EXECUTING, keep driving until a result comes 6n. If the screen indicates OUT OF CONDITION, go to step 11 and recheck.