O2 Sensor Heater Failure

NAME OF CODE
Upstream O2 Sensor Heater Failure

WHEN MONITORED
With the engine at idle immediately after a cold start (engine < 147° F and battery temp +/- 27° F of engine temperature).

SET CONDITION
O2 sensor voltage > 3V for 30 to 90 seconds.

THEORY OF OPERATION
The oxygen sensor is a voltage generating device. The Powertrain Control Module (PCM) receives exhaust gas information from this O2 sensor. The sensor detects exhaust gas content by a galvanic reaction within the sensor that produces a voltage. After measuring the amount of oxygen in the exhaust gases. This O2 sensor serves as an indicator of oxygen content. The heater element helps the O2 sensor quickly reach a normal and steady operating temperature, which is required for proper emission control.

POSSIBLE CAUSES
- Open heater element circuit
- 02 sensor failure
- 02 heater wiring
- Powertrain control module failure
- Connector terminals
- Connector wires