Fuel Control Heated Oxygen Sensors

Diagnose the Fuel Control Heated Oxygen Sensors for the following conditions:

- Heater Performance (time to activity on cold start)
- Slow Response
- Response Time (time to switch R/L or L/R)
- Inactive Signal (output steady at bias voltage - approximately 450 mV)
- Signal Fixed High
- Signal Fixed Low

FUEL CONTROL HEATED OXYGEN SENSORS
The main function of the fuel control heated oxygen sensor is to provide the PCM with exhaust stream information in order to allow proper fueling and maintain emissions within acceptable levels. After the sensor reaches the operating temperature, the sensor generates a voltage inversely proportional to the amount of oxygen present in the exhaust gases.

The PCM uses the signal voltage from the fuel control heated oxygen sensors in a closed loop in order to adjust the fuel injector pulse width. While in a closed loop, the PCM can adjust fuel delivery in order to maintain an air to fuel ratio which allows the best combination of emission control and driveability.

If the oxygen sensor pigtail wiring, connector or terminal are damaged, replace the entire oxygen sensor assembly. Do not attempt to repair the wiring, connector, or terminals. In order for the sensor to function properly, the sensor must have a clean air reference provided to it. This clean air reference is obtained by way of the oxygen sensor wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference. Any attempt to repair the wires, connectors or terminals could degrade oxygen sensor performance.