DTC Troubleshooting

DTC Troubleshooting: P0139, P0159, P0139, P0159

DTC P0139:

Rear Secondary HO2S (Bank 1, Sensor 2) Slow Response

DTC P0159:

Front Secondary HO2S (Bank 2, Sensor 2) Slow Response

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), or press the engine start/stop button to select the ON mode.

2. Clear the DTC with the HDS.

3. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

4. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- A/T in D, or M/T in 4th
- Drive at a steady speed between 55-75 mph (88-120 km/h) for 1 minute, then decelerate (with the throttle fully closed) for 10 seconds.

5. Monitor the OBD STATUS for DTC P0139 and/or P0159* 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, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM. 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 to LOCK (0), or press the engine start/stop button to select the OFF mode.

7. Replace secondary HO2S (Sensor 2) Secondary HO2S Replacement.

8. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

9. Reset the ECM/PCM with the HDS.

10. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.

11. Start the engine, and let it idle without load (A/T in P or N, M/T in neutral) until the radiator fan comes on.

12. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- A/T in D, or M/T in 4th
- Drive at a steady speed between 55-75 mph (88-120 km/h) for 1 minute, then decelerate (with the throttle fully closed) for 10 seconds.

13. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0139 and/or P0159* indicated?

YES -

Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM, then go to step 1.

NO -

Go to step 14.

14. Monitor the OBD STATUS for DTC P0139 and/or P0159* in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES -

Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 13, go to the indicated DTC's troubleshooting.

NO -

If the screen indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM, then go to step 1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 11.