DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P2270

DTC P2270 : Secondary HO2S (Sensor 2) Circuit Signal Stuck Lean

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Start the engine. Hold the engine speed at 3,000 rpm without load (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)
* Transmission in 4th
* Engine speed between 1,500-3,000 rpm
* Drive 30 seconds or more

-5. Monitor the OBD STATUS for DTC P2270 with the HDS.

Does the HDS indicate FAILED?
-YES- Replace the secondary HO2S (Sensor 2) Secondary HO2S Removal and Installation, then do the repair verification.
-NO- If the HDS 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. If the HDS indicates NOT COMPLETED, go to step 1-3 and recheck.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to ON (II).

-2. Reset the ECM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-3. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

-4. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.

-5. Test-drive under these conditions:
* Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
* Transmission in 4th
* Engine speed between 1,500-3,000 rpm
* Drive 30 seconds or more

-6. Monitor the OBD STATUS for DTC P2270 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
-PASSED- Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck.
-NOT COMPLETED- Meet the test condition, and check the OBD STATUS again.