1. Check for continuity between ECM/PCM connector terminal E20 and body ground.

Is there continuity?

YES | - | Repair open in the wire between the ECM/PCM (E4) and the secondary HO2S (Sensor 2) , then go to Step 21 .
NO | - | Repair open in the wire between the ECM/PCM (E20) and the secondary HO2S (Sensor 2), then go to Step 21 .

1. Turn the ignition switch OFF.

1. Replace the secondary HO2S (Sensor 2).

1. Reconnect all connectors.

1. Turn the ignition switch ON (II).

1. Reset the ECM/PCM with the HDS.

1. Do the ECM/PCM idle learn procedure.

1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (in Park or neutral) until the radiator fan comes on, then let it idle.

1. Test-drive under these conditions:
   - Engine coolant temperature above 70 °C (158 °F)
   - A/T in D position (M/T in 4th gear)
   - Engine speed at 2,000−3,000 rpm (min −1 )
   - Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

1. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES | - | If DTC P0138 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 28 .

1. Monitor the OBD STATUS for DTC P0138 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 on. If the screen indicates OUT OF CONDITION, go to Step 24 and recheck.

1. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.

1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (in Park or neutral) until the rdiator fan comes on, then let it idle.

1. Test-drive under these conditions:
   - Engine coolant temperature above 70 °C (158 °F)
   - A/T in D position (M/T in 4th gear)
   - Engine speed at 2,000−3,000 rpm (min −1 )
   - Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

1. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES | - | If DTC P0138 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 | - | If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. ■