DTC P0139: Secondary HO2S (Sensor 2) Slow Response

WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine, and let it idle without load (in P or N) until the radiator fan comes on.
Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
- Transmission in D
- Drive at a steady speed between 55-75 mph (90-120 km/h) for 1 minute, then decelerate (with the throttle fully closed) for 10 seconds
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, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the PCM. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to step 3 and recheck.
Turn the ignition switch to LOCK (0).
Replace secondary HO2S (Sensor 2) (see A/F SENSOR REPLACEMENT ).
Turn the ignition switch to ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Start the engine, and let it idle without load (in P or N) until the radiator fan comes on.
Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
- Transmission in D
- Drive at a steady speed between 55-75 mph (90-120 km/h) for 1 minute, then decelerate (with the throttle fully closed) for 10 seconds
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0139 indicated?

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

NO -Go to step 14.
Monitor the OBD STATUS for DTC P0139 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 instep 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 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 or NOT COMPLETED, go to step 11.