OBD-II code · Powertrain (generic, extended)
P220A NOx Sensor Supply Voltage Circuit (Bank 1 Sensor 1)
The supply voltage rail to the NOx sensor on bank 1 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.
Is it safe to drive with P220A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyFuse, harness break, or short
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)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor, Nox Sensor Supply Relay
Related codes
- P220BNOx Sensor Supply Voltage Circuit (Bank 1 Sensor 2)
- P220CNOx Sensor Supply Voltage Circuit (Bank 2 Sensor 1)
- P220DNOx Sensor Supply Voltage Circuit (Bank 2 Sensor 2)
- P2207NOx Sensor Circuit Range/Performance (Bank 2)
- P2208NOx Sensor Heater Circuit (Bank 2)
- P2209NOx Sensor Heater Sense Circuit Range/Performance (Bank 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.