Set Condition

The Powertrain Control Module (PCM) detects that the O2 Sensor Heater element resistance is above 4640 Ohms for 4 tests during this ignition cycle. The PCM cannot directly measure the heater resistance, therefore the heater rationality is determined as follows: A 1mA current is pulsed through the O2 Sensor circuit and the voltage across the sensor is measured. The heater health is inferred by this measurement. To avoid overheating and damaging the O2 Sensor, the resistance can only be measured periodically and during fuel cutoff. Two trip fault. Three good trips to turn off the MIL.