Technical Definition:

O2 Circuit Low Voltage (Bank 2, Sensor 2)

Technical Description:

This code refers to a fault in the post-catalyst o2 sensor on Bank 2. First, a basic run-down of the catalyst: The Catalytic Converter is used to help control tailpipe emissions, to “clean up” the exhaust, if you will. The PCM (Powertrain Control Module) uses the signal from the heated oxygen sensor to the rear of the catalyst to monitor the catalyst’s efficiency by comparing it to the o2 sensors in front of the catalyst.

Possible Causes:

• Air leaks in exhaust in front of o2 sensor giving false reading
• Engine running excessively lean
• O2 sensor connector damaged/corroded
• 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 (only if PCM is trying to add fuel to compensate for low o2 sensor voltage reading)
• Engine running lean (only if vacuum leak is large enough that PCM can’t compensate by adding fuel)
• Poor idle

O2 Sensor Circuit Low Voltage Bank 2 Sensor 2

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

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

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust