Diagnostic article Generic OBD-II
P2199: intake-temperature correlation depends on airflow and boost state
The GM P2199 example compares intake-temperature signals under specified airflow, vehicle-speed and pressure-ratio conditions, with an unresolved lower comparison.
Read before applying this article
Documented application
GM 2009 09OBDG02 Engine Diagnostics, cited intake-air temperature correlation 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.
P2199 compares intake-air temperature sensors 1 and 2 in the cited GM table. Its diagnostic context includes airflow, vehicle motion and pressure ratio. It is therefore not a universal rule that both sensors must show the same temperature during an arbitrary stationary scan.
Preserve the comparison's operating window
The source lists mass airflow between 6.7 and 83.3 g/s, vehicle speed above 34.4 mph and a boost-to-ambient pressure ratio below 1.4. The printed upper comparison is sensor 1 minus sensor 2 greater than 24.8°C.
A second line prints a lower comparison at 20.3°C without clearly identifying its relationship to failure or recovery. This article does not silently treat it as a second failure rule or a verified pass threshold. The exact branch and timing interpretation needs the applicable calibration information.
Keep sensor identity with the recorded values
A technician should preserve both temperature reports and the airflow/pressure state from the event. Comparing a reading under boost with an unrelated low-flow observation would lose the qualification that makes this correlation check meaningful.
The table does not prove which temperature sensor is biased or prescribe replacement of an airflow assembly. It also provides no universal sensor-location mapping. Use the correct vehicle procedure to establish the signal paths and evaluate their relationship. The stated speed boundary is monitor context, not an instruction to conduct an improvised road test while diagnosing an unresolved engine-control fault.
Source and applicability
GM 2009 09OBDG02 Engine Diagnostics, cited intake-air temperature correlation 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
Intake Air Temperature Sensor 1/2 Correlation
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