Technical Definition:

O2 Circuit (Bank 2, Sensor 3)

Technical Description:

The O2 (oxygen) sensors measure oxygen content in the exhaust, whether rich or lean. The PCM (powertrain control module) then uses this information to regulate fuel injector pulse in order to keep the proper air:fuel ratio. The O2 sensors are very important for the proper operation of the engine.

Possible Causes:

• Bad O2 sensor
• Signal shorted to voltage
• Wiring problems due to contact with exhaust components
• Holes in exhaust near O2 sensor

Possible Symptoms:

• MIL (Malfunction Indicator Lamp) illumination
• Decrease in MPG
• Increase in tailpipe emissions

O2 Sensor Circuit Malfunction Bank 2 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 2 Sensor 3
– Heated Oxygen Sensor Bank 2 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 2 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust