What it means
The supply voltage rail to the NOx sensor on bank 2 sensor 2 is faulty — typically a fuse, harness break, or short. NOx sensors need a clean stable supply for the heater and the wide-band measurement cell.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 sensor 2 NOx sensor uses a stable electrical supply for its heater and measuring electronics. P220D sets when the control module detects a fault in that sensor's supply voltage circuit, which may be in the wiring, connector, fuse, or sensor.
Common causes
Most likely first.
- Open or short in the sensor power wiring
- Poor electrical connection or corroded connector
- Blown fuse or faulty power supply
- NOx sensor internal fault
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
How to diagnose it
- Read freeze-frame data and related codes to find when the bank 2 sensor 2 supply fault was recorded.
- Locate bank 2 sensor 2 using vehicle-specific information and inspect its connector and harness for corrosion, loose contacts, heat damage, or chafing.
- Follow the wiring diagram to check its supply fuse and connections, and inspect for a short before replacing a blown fuse.
- Measure supply and ground at the bank 2 sensor 2 connector under the manufacturer's specified conditions and compare readings with the manufacturer's specification.
- If supply and wiring are sound, check the sensor for an internal fault and verify the module feed using the manufacturer's procedure.
Common fixes
- Reconnect or clean the bank 2 sensor 2 supply connector.
- Repair an open, shorted, or heat-damaged sensor 2 supply wire.
- Replace a failed fuse after correcting the fault that caused it to open.
- Repair a poor power or ground connection in the bank 2 sensor 2 circuit.
- Replace the bank 2 sensor 2 NOx sensor if it fails internal supply circuit tests.
Can I keep driving?
The vehicle may continue to run, but the bank 2 sensor 2 may not heat or measure NOx correctly, affecting emissions control and inspection readiness. Address any DEF warning or start countdown promptly.
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.