P0587 indicates a low voltage condition in the cruise control vent control circuit, meaning the system is detecting insufficient voltage to operate the vent control motor or solenoid.
Frayed wires, loose pins, or corrosion can drop voltage below the sensor’s threshold, triggering the low‑voltage code.
The motor that opens/closes the vent may have internal shorts or mechanical wear that cause it to draw excessive current, resulting in low voltage detection.
A bad ground path increases resistance, lowering the voltage seen by the control module.
Although rare, the internal driver that supplies voltage to the vent circuit can fail, causing a low‑voltage reading.
In most cases no. The PCM is rarely the cause of a low‑voltage vent control circuit; wiring, connectors, grounds, or the vent motor are far more common culprits.
Yes. The code is stored as a hard‑set fault; if the underlying voltage issue remains, the code will reappear after the next cruise‑control activation.
The vent control circuit operates the actuator that opens or closes the air‑flow vent for cruise‑control‑linked functions; a fault does not affect temperature control but can disable the vent button on the steering wheel.
Disconnect the battery before pulling connectors, use a multimeter set for DC voltage, and follow the vehicle’s service manual to avoid accidental short circuits.