P22A7NOx Sensor Heater Sense Circuit Range/Performance (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P22A7 means the heater feedback of the rear NOx sensor on bank 1 shows a heater that does not reach or hold its target, although no open or short is found. GM's 3.0L LZ0 and 2017 small diesels compare the measured heater resistance with its target once supply has been in range for 45 s and dew point passed 180 s ago (Type B); the 6.6L LML fails the sensor if its heater never reports set-point temperature. VW's 2014 Touareg TDI allows 180 s after dew point; Ford uses the code as a signal readiness check. Ford traced it on 2017 to 2020 6.7L Super Duty trucks to water in the NOx connectors (TSB 20-2067, new harness 14406) and on 2023 models to that harness chafing on the EGR cooler, with fuse F18 blown (SSM 51750/51791). Nissan's NTB16-048 replaces the outlet sensor.
- What you may notice
- Malfunction indicator lamp on
- Outlet NOx sensor becomes ready late or not at all
- Often stored with U029E or other NOx sensor codes
- Likely causes
- LikelyAged heater or element in the outlet NOx probe
- PossibleWater in the NOx sensor connectors (Ford 6.7L 2017-2020, TSB 20-2067)
- PossibleHarness chafed on the EGR cooler with blown supply fuse (Ford 6.7L 2023)
- RareWeak supply to the sensor module limiting heater power
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.