Circuit/System Verification

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Ignition ON, observe the DTC information with a scan tool. Verify no B52 HO2S heater DTCs are set.
- If a HO2S heater DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Run the engine for more than 5 minutes.
Engine idling at operating temperature, observe the appropriate B52 HO2S parameter with a scan tool. Verify the following:
- The B52 HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
- The B52 HO2S 2 value 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.