P2432 indicates the powertrain control module (PCM) has detected a voltage signal from the secondary air injection (SAI) system air flow/pressure sensor on bank 1 that is below the expected minimum. This sensor monitors pressure or flow in the SAI circuit to verify proper operation during cold starts.
The sensor itself is the most common failure point due to exposure to heat, moisture, and exhaust byproducts.
Corroded, broken, or shorted wires and connectors in the sensor circuit can pull the signal voltage low.
Restricted hoses, a stuck check valve, or leaks downstream of the sensor can cause abnormal pressure readings.
If the pump does not run or the relay fails, the sensor may report no flow/pressure, triggering a low-circuit code.
An internal driver or reference-voltage issue in the PCM can produce a false low reading, but this is uncommon.
Almost never. The PCM is the last item on the cause list and should only be considered after the sensor, wiring, and SAI mechanical components have been thoroughly tested and ruled out.
The vehicle will usually run normally, but it will not pass an emissions inspection and the SAI system will not function correctly during cold starts, increasing tailpipe emissions.
No. The SAI air flow/pressure sensor monitors the secondary air injection system only; it is separate from the upstream/downstream oxygen sensors used for fuel control.
The SAI system operates primarily during cold starts. Moisture condensation and thermal cycling in winter accelerate sensor and wiring degradation, making faults more likely to appear then.