Diagnostic article Generic OBD-II
P2436: Bank 2 AIR pressure rationality depends on pump state
Understand how Bank 2 secondary-air pressure is compared with barometric pressure and why pump state changes the comparison.
Read before applying this article
Documented application
GM 2009 09OBDG11 Engine Diagnostics, Dual Bank section, only the cited secondary-air monitor. Physical bank location and per-code vehicle applicability require vehicle-specific service information.
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.
P2436 is a Bank 2 secondary-air pressure performance code in the cited GM dual-bank system. Its monitor compares AIR pressure with estimated barometric pressure and considers the quality of that comparison. This is a plausibility test, distinct from a signal simply falling outside its electrical limits.
Pump on and pump off are different comparisons
With the pump commanded off, the listed error boundaries are more than 10 kPa above or below BARO. With the pump commanded on, the table lists a positive difference above 10 kPa. Applying the same two-sided comparison to both states would misrepresent this calibration.
The accumulated test weight also depends on distance from the last barometric update. That matters diagnostically: two snapshots with the same pressure difference need not have the same evidentiary weight if the controller's BARO estimate was refreshed under different circumstances.
Reproduce the qualified observation
The source requires more than 7,200 seconds of engine-off time, intake temperature above 5°C and coolant between 5°C and 80°C. Relevant AIR circuit, reference and airflow faults can inhibit testing. Consequently, a later warm-engine reading that agrees with BARO does not demonstrate that the original qualified comparison has passed.
A useful record pairs AIR pressure, estimated BARO, commanded pump state and monitor status. P2435 instead targets a signal that remains unresponsive in range, while P2437 and P2438 address electrical extremes. Those distinctions help decide whether to investigate reference quality, response or circuit validity without treating this code alone as a sensor replacement instruction.
Source and applicability
GM 2009 09OBDG11 Engine Diagnostics, Dual Bank section, only the cited secondary-air monitor. Physical bank location and per-code vehicle applicability require vehicle-specific service information.
General Motors source, physical page 146 · General Motors source, physical page 147 · General Motors source, physical page 148
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
AIR System Air Flow/Pressure Sensor Circuit Range/Performance Bank 2
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