Originally Posted by nate4027
Not sure what the O2 heater circuit does.
Exactly what it sounds like. It preheats the 02 sensor. O2 sensors, like catalytic converters, need to be up to temperature quickly to work most efficiently.
It should throw a code unless your SVT has a custom tune in place.
P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected.
Short to VPWR in harness or HO2S.
Water in harness connector.
Open VPWR circuit.
Open GND circuit.
Low battery voltage.
Corrosion or poor mating terminals and wiring
Damaged HO2S heater.