Diagnostic article Generic OBD-II
P2191: high-load lean correction is evaluated after adaptation stabilizes
The GM P2191 example evaluates the upper multiplicative fuel-correction limit under closed-loop, warmed and otherwise qualified operating conditions.
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Documented application
GM 2009 09OBDG04 Engine Diagnostics, cited upper multiplicative fuel correction example only. Per-code vehicle, engine and calibration applicability has not been established; use the matching vehicle procedure.
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.
P2191 is the upper-side multiplicative fuel-correction diagnostic in this GM table. The general description associates it with a lean condition at higher load. The source's actual observation is that the applicable correction factor exceeds its calibrated limit; it does not identify a single failed fuel or air component.
Adaptation must be eligible
The printed upper boundary is a correction factor above 1.175. The table requires closed-loop fuel operation, active long-term adaptation, a warmed engine, restricted intake-temperature conditions and purge control inactive. It also includes fuel-level and accumulated-air-mass qualifications.
The monitoring discussion allows adaptation time after engine start. Consequently, an isolated correction value during startup or an ineligible operating state cannot be treated as the same qualified result. The table further says that a diagnostic pass after detection needs similar conditions to be encountered again.
Compare the same type of correction
Keep the multiplicative correction and its load/airflow context together. The adjacent additive correction used at low speed and low load is a different diagnostic path; its percentage limits cannot replace the multiplicative factor for P2191.
A technician must use the vehicle-specific procedure to separate air measurement, fuel delivery, leakage and other supported causes. This parameter table does not provide that isolation sequence or prescribe a part replacement. Verification should revisit comparable qualified conditions and the relevant correction behavior, rather than relying on a code reset or an unrelated idle reading.
Source and applicability
GM 2009 09OBDG04 Engine Diagnostics, cited upper multiplicative fuel correction example only. Per-code vehicle, engine and calibration applicability has not been established; use the matching vehicle procedure.
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
System Too Lean at Higher Load Bank 1
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