Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0586 Cruise Control Vent Control Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Older engines without electronic throttle use a vacuum cruise servo on the throttle cable: a vacuum valve (closed when unpowered) opens the throttle with intake vacuum, a vent valve (open when unpowered) holds or releases it, and a dump valve fed through the brake switch vents it when braking. Where the engine module drives these valves, it checks each circuit and switches cruise off; CARB treats this as emission-neutral, usually without warning lamp. P0586 concerns the vent valve circuit: an open circuit, checked with cruise control active. An unpowered vent valve stays open, so the servo cannot hold vacuum.

Likely causes

Servo connector or terminals
Vent valve in the servo faulty
Vent control line open or shorted to ground
Engine module driver

Symptoms

  • Cruise control cannot be engaged or switches off
  • Cruise indicator goes out or flashes (depending on vehicle)
  • Usually no check engine light, code stored only

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–300
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

cruise control servoservo solenoid valvesservo wiringengine control module

Related codes

P0587P0588P0582P0594

References: patents.google.com, patents.google.com, law.cornell.edu.