What it means
O2 negative current line on bank 2 sensor 2 stuck low — short to ground. 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 negative-current control line as the sinking side of its pumping-current circuit. The engine control module sets P22C0 when that circuit reads below its expected range; the low reading does not by itself establish a short to ground.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 see when the negative-current reading is low.
- Inspect the negative-current wire and connector for chafing, corrosion, loose pins, or heat damage near the exhaust.
- Use the wiring diagram to check the Bank 2 Sensor 2 negative-current circuit for a short to ground.
- With the sensor disconnected as directed by service information, test the harness for shorts to ground and continuity against the manufacturer's specification.
- If the wiring passes, test the sensor and control-module circuit with the manufacturer's diagnostic procedure.
Common fixes
- Repair a negative-current wire shorted to ground or damaged by chafing.
- Clean or repair corroded connector contacts and secure loose terminals.
- Replace the Bank 2 Sensor 2 oxygen sensor if its negative-current circuit fails testing.
- Repair the control module only if its circuit fault is confirmed.
Can I keep driving?
Cautious driving is generally possible if the engine runs normally, but the Bank 2 Sensor 2 signal may be unreliable and emissions monitoring can be affected. Limit driving if hesitation or rough running worsens.
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.