P22A5 code meaning
NOx Sensor Heater Control Circuit High (Bank 1 Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P22A5 means
P22A5 is the opposite of P22A4: the heater control line of the rear NOx sensor on bank 1 has a short to supply voltage. The sensor module then cannot switch or regulate the heater, and the element risks running too hot or the module shuts the heater off to protect it. GM describes the check on the 3.0L LZ0 as a battery short at the heater control pin, 80 failures in 160 samples with dew point reached and supply above 9.9 V, Type B after two trips; the 2017 small diesels test the H+ supply pin of the Gen 3.0 sensor with 20 failures in 40 samples. GM bulletin 24-NA-094 lists P22A5 among codes an LZ0 software update clears on 2024 pickups. No public bulletin names a hardware fix. P22A3 is the open circuit, P22A4 the ground short, P2207 the front sensor.
P22A5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P22A5
- Malfunction indicator lamp on after two trips
- Heater switched off, outlet NOx sensor not ready
- SCR warning on the display
Common causes of P22A5
- Most likelyHeater circuit inside the sensor shorted to supply voltage
- PossibleProbe lead or connector touching a powered conductor
- Less likelySoftware anomaly (GM 3.0L LZ0 2024, bulletin 24-NA-094)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Nox sensorNox sensor heater
What each part of P22A5 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). |
| A5 | The exact fault in that area. |
What to do next
- Note P22A5 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 P22A5
What does P22A5 mean?
P22A5 means "NOx Sensor Heater Control Circuit High (Bank 1 Sensor 2)". P22A5 is the opposite of P22A4: the heater control line of the rear NOx sensor on bank 1 has a short to supply voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with P22A5?
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 P22A5 fail an emissions test?
Yes, it can. P22A5 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 P22A5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P22A5 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.