( TF09EABK72100090138FAAT00 )
DTC Troubleshooting: P0138 (63)
DTC P0138:
 Secondary HO2S (Sensor 2) Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch to ON (II).
  1. Clear the DTC with the HDS.
  1. 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.
  1. Check the HO2S S2 in the DATA LIST with the HDS.
Does the voltage stay at 1.27 V or more?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM.■
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the secondary HO2S (Sensor 2) 4P connector.
  1. Connect secondary HO2S (Sensor 2) 4P connector terminals No. 1 and No. 2 with a jumper wire.
  1. Turn the ignition switch to ON (II).
  1. Check the HO2S S2 in the DATA LIST with the HDS.
Does the voltage stay at 1.27 V or more?
YES -
Go to Step 11 .
NO -
Go to Step 20 .
  1. Turn the ignition switch to LOCK (0).
  1. Remove the jumper wire from the secondary HO2S (Sensor 2) 4P connector.
  1. Connect secondary HO2S (Sensor 2) 4P connector terminal No. 2 to body ground with a jumper wire.
  1. Turn the ignition switch to ON (II).
  1. Check the HO2S S2 in the DATA LIST with the HDS.
Does the voltage stay at 1.27 V or more?
YES -
Go to Step 16 .
NO -
Repair open in the wire between the ECM/PCM (B34) and the secondary HO2S (Sensor 2), then go to Step 22 .
  1. Turn the ignition switch to LOCK (0).
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector B (49P).
  1. Check for continuity between ECM/PCM connector terminal B36 and body ground.
Is there continuity?
YES -
Go to Step 30 .
NO -
Repair open in the wire between the ECM/PCM (B36) and the secondary HO2S (Sensor 2), then go to Step 22 .
  1. Turn the ignition switch to LOCK (0).
  1. Reconnect all connectors.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM/PCM with the HDS.
  1. 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.
  1. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 70 °C (158 °F)
    • A/T in D (M/T in 4th gear)
    • Engine speed between 1,500−3,000 rpm (min −1 )
    • Drive about 1 minute or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0138 indicated?
YES -
Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM, then go to Step 1 .
NO -
Go to Step 29 .
  1. Monitor the OBD STATUS for DTC P0138 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 28 , go to the indicated DTC's troubleshooting.■
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 or NOT COMPLETED, go to Step 26 .
  1. Reconnect all connectors.
  1. 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.
  1. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 70 °C (158 °F)
    • A/T in D (M/T in 4th gear)
    • Engine speed between 1,500−3,000 rpm (min −1 )
    • Drive about 1 minute or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0138 indicated?
YES -
Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 32 . If the ECM/PCM was substituted, go to Step 1 .
NO -
Go to Step 35 .
  1. Monitor the OBD STATUS for DTC P0138 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in Step 34 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 32 . If the ECM/PCM was substituted, 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 30 .