DTC codes / P24xx · Auxiliary emission controls / P2439
P2439 indicates that the powertrain control module (PCM) has detected an intermittent or erratic signal from the bank 2 secondary air injection (AIR) system air flow or pressure sensor. The PCM monitors this sensor to verify that the AIR system delivers the expected air flow during cold starts, and this code sets when the signal drops out or fluctuates beyond acceptable limits.
Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.
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