What it means
The supply voltage rail to the NOx sensor on bank 2 sensor 1 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 1 NOx sensor needs a stable supply voltage for its heater and measurement electronics. P220C means the control module has detected a fault in that sensor's supply circuit, which can be caused by a feed, ground, connector, fuse, or sensor problem.
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
- Check freeze-frame data and related codes to see when the bank 2 sensor 1 supply fault occurred.
- Use vehicle information to locate bank 2 sensor 1, then inspect its connector and wiring for looseness, corrosion, exhaust heat damage, and chafing.
- Trace the bank 2 sensor 1 supply through the wiring diagram and inspect its fuse and connections, checking for a short before replacing a blown fuse.
- Measure supply and ground at the sensor connector under the conditions specified by the manufacturer and compare with the manufacturer's specification.
- If the feed is correct, test the sensor for an internal fault and verify the module supply using the manufacturer's circuit procedure.
Common fixes
- Clean and secure the bank 2 sensor 1 supply connector.
- Repair damaged or shorted bank 2 sensor 1 wiring.
- Replace a failed fuse after correcting the circuit fault that caused it to blow.
- Restore a poor power or ground connection in the sensor 1 circuit.
- Replace the bank 2 sensor 1 NOx sensor if it fails internal circuit tests.
Can I keep driving?
Driving may be possible, but the bank 2 sensor 1 may not heat or measure NOx reliably, which can increase emissions and cause an inspection failure. If DEF warnings or a start countdown appear, have the fault repaired 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.