What it means
Bank 2 counterpart to P2244. The reference voltage at the wide-band oxygen sensor on bank 2, sensor 1 is outside its expected range and falsifies the lambda calculation.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The upstream wide-band oxygen sensor on bank 2 uses a reference voltage to interpret its sensing-cell signals, and the engine control module monitors that reference at Sensor 1. This code sets when the bank 2 reference circuit behaves outside its expected range or performance, making the module's mixture calculation less dependable.
Common causes
Most likely first.
- Reference circuit drift in ECU
- High resistance in reference wiring
- Sensor element aged beyond calibration window
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 compare Bank 2 Sensor 1 live readings with the upstream sensor on bank 1 to identify whether the bank 2 reference is unstable or implausible.
- Inspect the Bank 2 Sensor 1 connector and wiring for corrosion, loose pins, heat damage, or signs of intermittent contact.
- Check reference-circuit resistance and terminal condition against the manufacturer's specification, using the wiring diagram to identify the correct circuit.
- Monitor the circuit while gently moving the harness to reveal intermittent resistance, then compare sensor behavior with the manufacturer's diagnostic procedure.
- If wiring and terminals pass, test the sensor element and module reference output separately before replacing parts.
Common fixes
- Clean or repair high-resistance Bank 2 Sensor 1 connector terminals.
- Repair corroded, damaged, or intermittently open reference wiring.
- Replace the Bank 2 Sensor 1 sensor if its reference behavior remains outside specification after circuit checks.
- Repair the module reference output only if testing confirms the fault is there.
Can I keep driving?
You can usually drive cautiously, but poor bank 2 mixture feedback can increase fuel consumption or cause rough running and excess emissions. Reduce driving if symptoms worsen and address the code before an emissions inspection.
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.