Chrysler
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    HO2S Heater Circuit Conditions
Cause:
    Cold engine startup requirement met (ECT sensor input under 147°F, BTS input within ± 59°F of ECT sensor input), then the test started and the PCM detected that the front HO2S-11 signal was over 3v for 30-90 seconds.

Ford
Type:
    Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description:
    HO2S Heater Circuit Conditions
Cause:
    Engine running for 1 minute, then the PCM detected an open or short in the HO2S heater circuit

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 CKP, ECT, EGR, EVAP, Fuel Trim, Fuel Injector, IAT, MAP, Misfire or TP sensor codes set, ECT and IAT sensor inputs less than 95°F and within 11°F of each other at startup, average MAF sensor airflow for sample period less than 20 g/sec, system voltage from 8-18v, then the PCM detected that the HO2S-11 signal remained within 150 mv of bias voltage (450 mv) for over 30-90 seconds (actual time is from 42 seconds up to 2 minutes).