Diagnostic article Generic OBD-II
P219B: Bank 2 air-fuel imbalance is evaluated after fuel adaptation
Understand Ford P219B imbalance monitoring, its operating cells and why a normal average fuel trim does not replace the bank-specific test.
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Documented application
Ford 2024–2025 gasoline OBD operation summary, July 16 2024 revision; only the documented monitor variants. No individual model, engine or calibration fitment inferred.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
Ford identifies P219B as bank 2 air-fuel ratio imbalance. The monitor runs after the fuel system has adapted and evaluates a bank-specific imbalance ratio. It is not merely the same result as a bank-average lean or rich fuel-trim code.
Adaptation and stable operating cells are prerequisites
The source requires closed-loop control, completed fuel adaptation and eligible engine speed/load cells. It also limits throttle-rate changes and excludes purge transitions. Those restrictions matter because changing operating conditions can obscure the imbalance evidence.
Ford lists 300–700 seconds to complete the monitor and requires healthy oxygen-sensor, fueling, misfire and related systems. A brief smooth idle or an uncompleted monitor does not reproduce this evaluation. Likewise, a reasonable average trim cannot by itself prove that the bank's imbalance ratio passed.
Read the bank 2 result and its units
The published threshold is a bank 2 imbalance ratio above 0.75. Mode $06 monitor $82, test $80 exposes the bank 2 ratio and maximum limit as a unitless quantity. Do not reinterpret 0.75 as a voltage, pressure or direct percentage of one cylinder's fuel delivery.
Preserve the ratio, limit, completion status and operating conditions. The code identifies a monitored imbalance, but the summary does not determine which cylinder or component caused it. Further engine-specific diagnosis is needed before selecting an injector, ignition or mechanical repair. Verification should include a completed adapted-fuel imbalance check, not only cleared memory.
Source and applicability
This explanation covers the cited Ford monitor variants, not every vehicle displaying this code. Match the engine, sensor architecture and calibration before applying numerical limits.
Ford OBD summary, PDF page 24, Ford OBD summary, PDF page 25.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Bank 2 Air-Fuel Ratio Imbalance
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT