What does code P1540 mean?

Q: What does code P1540 mean?

A/C System High Pressure. P1540 on a GM vehicle means the powertrain control module (PCM) has detected that the air conditioning (A/C) system refrigerant pressure has risen above the safe operating threshold. The PCM monitors the A/C pressure sensor and sets this code when the signal indicates excessive high-side pressure, typically to protect the compressor and related components from damage.

DTC codes / GM codes / P1540

P1540 · GMA/C System High Pressure

P1540 on a GM vehicle means the powertrain control module (PCM) has detected that the air conditioning (A/C) system refrigerant pressure has risen above the safe operating threshold. The PCM monitors the A/C pressure sensor and sets this code when the signal indicates excessive high-side pressure, typically to protect the compressor and related components from damage.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.