P0594: Cruise Control Servo Control Circuit / Open
MediumPowertrainCruise Control
What does P0594 mean?
P0594 is a diagnostic trouble code indicating "Cruise Control Servo Control Circuit / Open". This means there is an electrical break in the cruise control wiring — a connector may be unplugged, a wire broken, or a component has failed internally. The ECU detected no signal where it expected one.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- Intermittent warning lights
- Erratic gauge readings
Estimated repair cost
Typical range in Australia (parts + labour)
$80 – $400 AUD
Common causes
- Damaged or corroded wiring harness
- Loose or disconnected electrical connector
- Failed cruise control sensor or actuator
- Blown fuse in the related circuit
- Poor ground connection
What should you do?
This code sits in a driver assistance system such as parking sensors, cruise control, tyre pressure monitoring or a camera. The car drives normally, but the assistance may be off or, worse, half working. Do not rely on it until it has been diagnosed.
Get a diagnosis for YOUR car
Code P0594 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.