DTC Troubleshooting: P0138 (63)
  1. Check for continuity between ECM/PCM connector terminal C27 and body ground.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair open in the wire between the ECM/PCM (C27) and the secondary HO2S (Sensor 2), then go to Step 21 .
  1. Turn the ignition switch to LOCK (0).
  1. Replace the secondary HO2S (Sensor 2).
  1. Reconnect all connectors.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM/PCM with the HDS.
  1. Do the ECM/PCM idle learn procedure.
  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
    • 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 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. If any other Temporary DTCs or DTCs were indicated in Step 27 , 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 25 .
  1. Reconnect all connectors.
  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 (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.
  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
    • 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 31 . If the ECM/PCM was substituted, go to Step 1 .
NO -
Go to Step 34 .
  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 33 , 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 31 . 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 31 .