Chrysler
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    HO2S Heater Fault Conditions
Cause:
    Cold engine startup requirement met (ECT sensor input less than 147°F, BTS ambient air reading within ± 27-59°F of ECT input), engine at idle speed, then the test started and the PCM detected that the rear HO2S-13 voltage was more than 300 mv for 30-90 seconds.

Generic
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    O2 Sensor Heater Circuit

GM
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    HO2S Heater Circuit Conditions
Cause:
    No PCM or TCM codes set, ECT/IAT inputs both under 95°F and within 11 °F of each other at startup, average MAF for sample period under 20 g/sec, then the PCM detected the HO2S-13 signal remained within ±150 mv of the bias voltage for 30-90 seconds