OBD-II trouble code
P22B6: O2 Sensor Pumping Current Trim Circuit Low (Bank 1 Sensor 2)
Application matters: GM 2021 Tahoe 2WD document 5504091 places P22B6 in NOx Sensor 2 diagnosis with continuous prerequisite-based monitoring. GM 24-NA-094 is a separate listed 2024 3.0L pickup software example. Match the installed system and current vehicle instructions.
A low pumping-current trim report for Bank 1 Sensor 2. Use the actual monitored calibration/control function; this is not universally a wet connector resistor read only at key-on.
Quick facts
- System
- Powertrain
- Category
- Oxygen Sensor
- Severity
- Low severity
- Driving guidance
- Depends on symptoms and vehicle guidance
- Repair cost range
- Get a vehicle-specific estimate after diagnosis.
- DIY difficulty
- Shop recommended
A code alone cannot establish whether driving is safe. Stop safely for a red brake or oil-pressure warning, overheating, severe misfire, stalling, or impaired braking or steering, and follow the owner's manual. Restraints faults can reduce crash protection even when the vehicle runs normally.
Part of a family with 26 codes
P22B6 is one of 26 codes covering oxygen sensor 2 control and trim faults. The identifier must be matched to the exact vehicle. Related codes can share a diagnostic approach, but their circuit, failure condition, and required tests can differ.
Browse every code in P2200–P22CA, or start from the full code library.
What does P22B6 mean?
P22B6 is the low condition in the Bank 1 Sensor 2 pumping-current trim group. Keep it separate from P22B5 circuit/open and P22B7 high. The vehicle defines the monitored trim function and the conditions used to assess it.
GM’s 2021 Tahoe 2WD procedure is a concrete counterexample to a key-on-only resistor explanation. It groups P22B6/P22B7 within calibrated NOx Sensor 2 diagnosis and specifies continuous monitoring after its engine, heater and supply prerequisites. The assembly also provides wide-band/digital-lambda information over serial-data electronics.
Software has its own bounded example. GM 24-NA-094 includes P22B6/P22B7 among possible software-anomaly reports for its listed 2024 Silverado 1500/Sierra 1500 3.0L applications. It directs an applicable calibration update or ordinary service diagnosis if no new calibration is available. A code that names a low circuit condition therefore does not universally prove moisture or a failed resistor.
Preserve the original scan before clearing or cycling power. The correct verification follows the demonstrated repair and actual monitor prerequisites, not a generic requirement for two key cycles or a long drive. An unchanged lamp state on one journey cannot independently approve a sensor, connector or software repair.
Possible causes
- A low trim-function fault established within the applicable sensing/interface system
- A connection or assembly problem confirmed by its protected diagnosis
- An incorrect or incompatible service part/connection where evidence supports it
- An applicable software condition on a vehicle matching the cited GM bulletin
Symptoms
- An engine/emissions warning with pumping-current trim low stored
- A calibration/control fault or rejected sensing information
- A persistent or occasional report under the manufacturer’s monitor conditions
- Related NOx, current-control, reference, heater or operating reports
Diagnostic steps
Save the full scan report, code status, and available freeze-frame data before clearing anything. Confirm the reporting module, any failure-type suffix, and the procedure for the exact vehicle. The steps below are an overview; use manufacturer specifications and safety procedures for testing.
- 1.Save the full manufacturer code, suffix, status, reporting module and failure records.
- 2.Identify the actual trim function, sensing assembly and monitor prerequisites.
- 3.Record the exact installed parts and recent wiring or programming work.
- 4.Have the prescribed protected connection, interface and component checks performed; confirm current bulletin/calibration applicability where relevant.
- 5.Choose the demonstrated repair or applicable update, including any required setup.
- 6.Complete the specified function/monitor verification. Do not substitute a resistor, deliberately wet connections or treat a generic key-cycle experiment as proof of repair.
Repair cost
Get a vehicle-specific estimate after diagnosis.
A trouble code alone does not price the repair. Ask the shop to identify the confirmed fault and itemize diagnosis, parts, labor, programming or calibration, and taxes.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with oxygen sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
These links are planning examples; the code does not confirm that any listed part has failed.
DIY vs shop
A qualified shop is recommended because this can involve manufacturer-grade tooling, training, or certification that most home setups do not have. Ask the technician what testing confirmed the repair.