What it means
Bank 2 counterpart of P2243. Reference voltage on the bank 2 sensor 1 wide-band probe is missing or out of tolerance.
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 measure exhaust mixture, and the engine control module monitors the reference circuit at Sensor 1. This code sets when that bank 2 reference is missing or outside the expected operating range, which can prevent reliable sensor feedback.
Common causes
Most likely first.
- Reference voltage line open on bank 2
- Bank 2 wide-band sensor failed
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
How to diagnose it
- Record freeze-frame data and compare Bank 2 Sensor 1 live readings with the corresponding upstream sensor on bank 1 to see whether the bank 2 reference fault is persistent.
- Inspect the Bank 2 Sensor 1 connector and harness for disconnection, corrosion, pulled wires, or heat damage.
- Check the bank 2 reference line for an open using the vehicle wiring diagram, tracing it from the sensor connector toward the module.
- Verify terminal fit and circuit continuity against the manufacturer's specification, moving the harness gently to expose intermittent opens.
- If the circuit is intact, test the Bank 2 Sensor 1 wide-band sensor and reference output following the manufacturer's procedure.
Common fixes
- Reconnect the Bank 2 Sensor 1 connector or secure a loose terminal.
- Repair an open or heat-damaged Bank 2 Sensor 1 reference wire.
- Replace the Bank 2 Sensor 1 sensor if it fails the specified test.
- Repair the module reference circuit if testing confirms the module is at fault.
Can I keep driving?
The vehicle may remain drivable, though the bank 2 upstream mixture feedback may be unreliable and fuel use or idle quality can worsen. Avoid extended driving if it runs poorly and repair the issue 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.