What it means
The reference voltage line for the wide-band O2 sensor on bank 2 sensor 2 is open. The reference is used as the floating mid-point for the pumping cell.
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 as the midpoint for its pumping cell. The engine control module sets P22BB when it detects an open in the Bank 2 Sensor 2 reference circuit, so the sensor may not provide usable feedback.
Common causes
Most likely first.
- Open reference voltage line
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
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 live data and related codes for Bank 2 Sensor 2 to confirm the reference-circuit fault is current.
- Inspect the Bank 2 Sensor 2 connector for a pushed-back or loose reference pin, corrosion, and signs of heat or water damage.
- Trace the reference wire between the sensor and control module, looking for a break, chafing, or damage near the exhaust.
- With power off and components isolated as directed by service information, test reference-wire continuity and connector contact against the manufacturer's specification.
- If the external circuit is intact, follow the manufacturer's procedure to distinguish an internal sensor fault from a control-module fault.
Common fixes
- Repair a broken or damaged Bank 2 Sensor 2 reference wire.
- Reseat or replace a pushed-back terminal and clean corroded connector contacts.
- Replace the Bank 2 Sensor 2 oxygen sensor if its internal reference circuit is confirmed open.
- Repair or replace the control module only after its internal circuit fault is verified.
Can I keep driving?
You can usually drive cautiously if the engine runs normally, but the fault can prevent reliable oxygen-sensor monitoring and may affect emissions-test readiness. Avoid continued driving if the engine begins running roughly or hesitating.
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.