DTC P2270: Secondary HO2S (Sensor 2) Circuit Signal Stuck Lean (2005-2006 models); DTC P2271: Secondary HO2S (Sensor 2) Circuit Signal Stuck Rich (2005-2006 models)

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

Turn the ignition switch ON (II).
Reset the ECM with the HDS (see ECM RESET ).
Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
Test-drive under these conditions:
- Engine coolant temperature above 176°F (80°C)
- Vehicle speed between 35 mph (56 km/h) or more
- Drive 1 minute or more
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P2270 or P2271 indicated?
1. YES - Replace the secondary HO2S (Sensor 2) (see SECONDARY HO2S REPLACEMENT ).
2. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the ECM.