What it means
The reference voltage line for the wide-band O2 sensor on bank 1 sensor 2 is open. The reference is used as the floating mid-point for the pumping cell.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 Sensor 2 is the downstream wide-band oxygen sensor after the engine’s first cylinder bank. Its reference voltage line provides the reference point for the sensor’s pumping cell; this code sets when that line is electrically open, preventing the module from using the reference as intended.
Common causes
Most likely first.
- Open reference voltage line
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Save freeze-frame data and check for related Bank 1 Sensor 2 oxygen sensor codes before testing the circuit.
- With the exhaust cool, inspect the sensor connector and wiring for damage, corrosion, or a terminal pushed back out of the connector body.
- Use the wiring diagram to identify the reference voltage line and check its continuity between the sensor and module as specified by the manufacturer.
- Check connector terminal fit and inspect for an open in the harness or at the sensor or module connection, following the specified isolation steps.
- If the wiring and terminals pass, test the sensor and module reference circuit using the manufacturer's procedure to locate an internal open.
Common fixes
- Repair an open or damaged reference voltage wire for Bank 1 Sensor 2.
- Reseat or replace a pushed-back or damaged connector terminal.
- Repair a poor connector contact or broken harness section.
- Replace the sensor or repair the module only if the specified tests confirm an internal open.
Can I keep driving?
A short drive is generally reasonable if the engine runs smoothly and no other serious warning is present, but arrange diagnosis soon. The module may have limited oxygen sensor feedback, which can affect fuel economy and emissions and lead to a failed emissions test.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.