What it means
O2 reference voltage on bank 2 sensor 2 above upper plausibility — short to B+. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The wide-band oxygen sensor after the Bank 2 catalytic converter uses a reference-voltage line to establish the pumping cell's electrical midpoint. The engine control module sets P22BE when the Bank 2 Sensor 2 reference circuit rises above its expected range; this reading does not by itself confirm a short to battery voltage.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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 check Bank 2 Sensor 2 live data and related codes to learn when the high reference reading occurs.
- Inspect the reference wire and sensor connector for corrosion, damaged pins, melted insulation, or wiring pinched against a powered circuit.
- Use the wiring diagram to test the reference circuit for a short to battery voltage and check the connector for unwanted contact with other terminals.
- With the sensor disconnected as directed by service information, test the harness for shorts to voltage and continuity against the manufacturer's specification.
- If the external wiring is intact, test the Bank 2 Sensor 2 reference circuit and control-module output according to the manufacturer's procedure.
Common fixes
- Repair a reference wire pinched against a power source or shorted to battery voltage.
- Clean or repair corroded terminals and replace damaged connector components.
- Replace the Bank 2 Sensor 2 oxygen sensor if testing confirms an internal reference-circuit fault.
- Repair the control module only if its output fault is confirmed.
Can I keep driving?
Cautious short trips are generally possible if the engine runs normally, but emissions monitoring may be unreliable and fuel use may increase. Arrange diagnosis soon and stop driving if the engine develops significant roughness or hesitation.
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.