Technical Definition:

O2 Circuit Low Voltage (Bank 1, Sensor 3)

Technical Description:

The Catalytic Converter is used to help control emissions. The PCM (Powertrain Control Module) uses the signal from the oxygen sensor to the rear of the catalyst to monitor the catalyst’s efficiency.

Possible Causes:

• Air leaks in exhaust in front of o2 sensor giving false reading
• O2 sensor connector damaged
• O2 sensor signal circuit is shorted to ground
• O2 sensor ground circuit is open
• O2 sensor has failed (it may be contaminated with fuel or coolant)
• PCM has failed

Possible Symptoms:

• MIL (Malfunction Indicator Lamp) illumination
• Engine performance issues
• Engine running rough
• Engine running rich
• Poor idle

O2 Sensor Circuit Low Voltage 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