P2524 indicates the powertrain control module (PCM) has detected a voltage on the A/C request B signal circuit that exceeds the calibrated maximum threshold. This circuit normally carries a low-voltage request signal from the HVAC control module or pressure sensor to the PCM to command compressor operation.
The signal wire between the HVAC control module and PCM has shorted to a power source, pulling the circuit voltage above the expected range.
The module or sensor supplying the request signal is outputting a voltage higher than specification due to internal failure.
Connector terminals are spread, contaminated, or corroded, creating a high-resistance path that can bias the signal voltage high.
Loss of the module's ground reference can cause its output drivers to pull the signal line toward battery voltage.
The PCM's internal input circuit for the A/C request B line has failed, biasing the reading high; this is rare and only considered after wiring and source module are verified.
Almost never. The code is caused by a wiring short, a faulty HVAC control module, or a bad sensor in the vast majority of cases. Replace the PCM only after the signal wire and source module have been proven good.
No. Low refrigerant typically sets pressure-related codes (e.g., P0530–P0534) but does not drive the A/C request signal voltage high.
Yes, the vehicle is drivable, but the A/C system will not operate. No engine performance or safety issue is caused by this code alone.
P2524 is a generic SAE code, but the exact circuit layout (A/C request B) and voltage thresholds vary by manufacturer. Always consult the specific service information for the vehicle being diagnosed.