P22B7 code meaning
O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P22B7 means
P22B7 is, going by its title, the high fault on the trim circuit belonging to bank 1's downstream wide-band probe. In GM's diesel tables (2016, 2018 and 2025 group 04) the code is a ceiling test on the oxygen value of the second NOx sensor: the 2016 table flags readings above 24 %, which is more oxygen than fresh air holds, in 100 of 200 samples. The test runs only while exhaust back-pressure stays below its limit, no exhaust brake is active and no NOx sensor pressure fault is pending; GM rates it Type B, two trips. GM bulletin 21-NA-149 lists it for the 3.0 Duramax LM2 alongside harness chafing. No public source gives a trim-resistor threshold. P22B5 is the open, P22B6 the low case, P22C4 bank 2. The lamp lights.
P22B7 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 P22B7
- Check engine light
- Downstream oxygen value above 21 % in live data
Common causes of P22B7
- Most likelyFaulty downstream NOx/oxygen sensor reporting excess oxygen
- PossibleChafed engine harness affecting the sensor lines (GM 3.0 LM2)
- Less likelyTrim or signal wire shorted to a voltage source
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank1 sensor2Nox sensorOxygen sensor wiringECM
What each part of P22B7 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). |
| B7 | The exact fault in that area. |
What to do next
- Note P22B7 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 P22B7
What does P22B7 mean?
P22B7 means "O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 2)". P22B7 is, going by its title, the high fault on the trim circuit belonging to bank 1's downstream wide-band probe. It is a generic code, so it means the same on every make.
Is it safe to drive with P22B7?
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 P22B7 fail an emissions test?
Yes, it can. P22B7 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 P22B7 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P22B7 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.