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

P0587 Cruise Control Vent Control Circuit Low

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. P0587 means the voltage at the vent valve driver is too low – the control line is shorted to ground, so the vent valve stays closed and the servo could hold vacuum; cruise control is therefore switched off, with braking safety from the dump valve. No manufacturer document available to us uses this code.

Likely causes

Vent control line shorted to ground
Valve coil shorted
Servo supply missing (P0595)
Engine module

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

P0586P0588P0583P0595

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