Circuit/System Verification

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON, observe the DTC information with a scan tool. Verify no HO2S heater DTCs are set.
- If a HO2S heater DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Run the engine for greater than 5 minutes.
Engine idling at operating temperature, observe the appropriate scan tool Heated Oxygen Sensor parameter. Verify the following:
- The HO2S 1 parameter should vary from below 200 mV to above 800 mV and respond to fueling changes.
- The HO2S 2 parameter should fluctuate at less than 380 mV or greater than 520 mV. The values should not remain within 380 mV and 520 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.