What it means
The bank 1 sensor 2 oxygen sensor positive current control circuit is below the expected range. The code does not by itself establish a short to ground or predict mixture and fuel-economy effects.
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. The control module monitors the sensor’s positive pumping-current circuit, which helps regulate oxygen in its reference chamber; this code sets when the circuit signal is lower than expected, though it does not by itself prove a short to ground.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Capture freeze-frame data and check live oxygen sensor data and related codes to see whether the fault is confined to Bank 1 Sensor 2.
- With the exhaust cool, inspect the sensor connector and harness for chafing, damaged insulation, corrosion, or loose terminals.
- Check the connector for poor contact and inspect the positive pumping-current wire where it passes near hot or moving parts.
- Use the wiring diagram and manufacturer's procedure to test the positive current circuit for a short to ground, excessive resistance, or an open.
- If the external circuit passes, test the wide-band sensor and module circuit as specified before replacing either component.
Common fixes
- Repair positive pumping-current wiring that is chafed or shorted to ground.
- Clean or repair corroded or loose Bank 1 Sensor 2 connector terminals.
- Replace damaged harness insulation or connector components.
- Replace the sensor or repair the module circuit only if the specified tests identify the fault there.
Can I keep driving?
A short drive is generally reasonable if the engine runs normally, but arrange diagnosis soon and avoid prolonged driving if rough running develops. Limited oxygen feedback can affect fuel economy and emissions, and may 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.