Diagnostic article Generic OBD-II
P0AB2: Outlet air is checked against the battery’s hottest module with the fan on
Interpret the GM P0AB2 outlet-temperature rationality monitor using fan command and valid module-temperature references.
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Documented application
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established.
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.
P0AB2 evaluates whether battery outlet-air temperature is credible relative to the highest battery-module temperature. The cited GM strategy expects the outlet reading not to exceed that reference by more than the allowed difference while the cooling fan is commanded on.
The comparison is directional
The failure quantity is outlet-air temperature minus the battery reference above 10°C. This is not an absolute-difference test: a much cooler outlet reading does not satisfy that stated inequality by itself.
The controller must be in run mode with appropriate low-voltage supply. The decision uses 90 failing samples within 100 at 100ms intervals. A long list of module-temperature, outlet-temperature and fan faults inhibits the check, continuing onto the following physical page.
Keep airflow command and sensor validity together
Record outlet temperature, the maximum-module reference, fan command and the validity of the contributing temperature channels. A fan-off workshop snapshot cannot be used as if it met the specified operating condition. Likewise, an invalid maximum-module reference undermines the comparison.
This monitor does not identify a blocked duct, wrong sensor or failed fan by itself. Its purpose is to test the temperature relationship under accepted conditions. The actual cooling-system and sensor diagnosis requires the matching vehicle procedure. High-voltage battery access and any fan intervention should be handled by qualified personnel using the appropriate isolation and moving-fan precautions.
Source and applicability
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established. GM PDF, page 238. GM PDF, page 239.
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
Hybrid/EV Battery Pack Air Temperature Sensor B Circuit Range/Performance
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