Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - High Fuel Consumption - Excessive Smoke from Exhaust

Possible Causes

- Front Heated Oxygen Sensor Bank 2 harness is open or shorted - Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection - Faulty Front Heated Oxygen Sensor Bank 2 - Inappropriate fuel pressure - Faulty fuel injectors - Intake air leaks may be faulty - Exhaust gas leaks

When Detected

The voltage from the sensor is constantly approx. 0.3V.

Tech Notes

Replacing the O2 Sensor 1 usually takes care of the problem

Description

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.