Technical Definition:

O2 Circuit (Bank 1, Sensor 3)

Technical Description:

The oxygen sensors are critical to the engine running properly. It basically informs the PCM (Powertrain Control Module) of oxygen content of the exhaust. The PCM then uses this information to regulate fuel injector pulse. Inaccurate or faulty O2 sensors can cause the PCM to add or take away fuel based on the faulty O2 sensor voltage which can cause a host of problems.

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 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust