What it means
The positive-current control circuit for the oxygen sensor at Bank 2 Sensor 1 is above its expected range. The code identifies a circuit condition, not a confirmed failed sensor.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
A wide-band oxygen sensor uses a pump cell to measure exhaust oxygen, while the engine control module monitors the positive-current control circuit for Bank 2 Sensor 1, the upstream sensor on bank 2. This code sets when the circuit reads above its expected range, which can indicate a short to a positive supply or an internal sensor fault.
Common causes
Most likely first.
- Pumping current line shorted to positive
- Sensor internally shorted
- Connector pins corroded - high contact resistance
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 compare Bank 2 Sensor 1 live readings with the upstream sensor on bank 1 to establish when the high-circuit condition occurs.
- Inspect the Bank 2 Sensor 1 connector and harness for corrosion, pin damage, chafing, or a wire contacting a positive supply.
- Use the wiring diagram to check the positive-current control line for a short to voltage and for damaged insulation near the sensor and exhaust.
- Check connector terminal fit and circuit continuity against the manufacturer's specification, moving the harness gently to look for a changing fault.
- If the external circuit checks out, test the sensor internally using the manufacturer's procedure before condemning it.
Common fixes
- Repair chafed wiring that is shorting the control line to a positive supply.
- Clean or replace damaged Bank 2 Sensor 1 connector terminals.
- Replace the Bank 2 Sensor 1 sensor if it has an internal short confirmed by testing.
- Repair a control module fault only after the sensor and wiring pass their checks.
Can I keep driving?
You can often drive cautiously, but fuel use may rise and the engine may idle roughly or hesitate. Limit driving if symptoms become pronounced, and address the fault before an 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.