P220B code meaning
NOx Sensor Supply Voltage Circuit (Bank 1 Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P220B means
P220B concerns the second NOx sensor on bank 1, the one behind the SCR catalyst whose reading proves how well NOx is being converted. Its operating voltage is outside the allowed band. Ford applies the same 8.5 to 16.5 V window as for the front sensor; GM's 3.0L LZ0 flags under 9.9 V (Type B), and VW's 2014 Touareg TDI compares battery and sensor supply, faulting a gap above 1.5 V. GM's 2018 Equinox and Terrain with the 1.6L diesel (LH7) could log P220B through a software issue; PIP5615A points to bulletin 19-NA-009 and an ECM calibration. Volvo and Mack class it as a supply problem, not a sensor failure. Without this sensor the catalyst efficiency check cannot run. P220A is the front sensor.
P220B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P220B
- Malfunction indicator lamp on
- Downstream NOx sensor shows no value
- SCR efficiency monitor stays incomplete
Common causes of P220B
- Most likelyFuse, relay or ground fault in the downstream sensor supply
- PossibleSupply wire to the rear sensor damaged under the vehicle
- Less likelyECM calibration (GM 1.6L LH7 2018, PIP5615A / 19-NA-009)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Nox sensor
What each part of P220B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| 0B | The exact fault in that area. |
What to do next
- Note P220B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P220B
What does P220B mean?
P220B means "NOx Sensor Supply Voltage Circuit (Bank 1 Sensor 2)". P220B concerns the second NOx sensor on bank 1, the one behind the SCR catalyst whose reading proves how well NOx is being converted. It is a generic code, so it means the same on every make.
Is it safe to drive with P220B?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P220B fail an emissions test?
Yes, it can. P220B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P220B to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P220B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.