Powertrain, generic · Vehicle speed, idle control and auxiliary inputs
P0525 Cruise Control Servo Control Circuit Range/Performance
Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo
P0525 concerns vehicles with a separate cruise control servo – a vacuum or electric actuator on the throttle cable driven by the engine module: the control circuit is electrically sound, but the response does not match the command. With electronic throttle the engine module controls the throttle itself, so the code hardly applies there. No manufacturer document available to us uses P0525. CARB names cruise control as the example of an emission-neutral diagnosis: switching it off as the default reaction suffices, so usually no warning lamp.
Likely causes
Servo worn or sticking, cable misadjusted
Vacuum leak at hose or diaphragm (vacuum servo)
Wiring, connector or fuse to the servo
Brake or clutch switch interrupting the servo release
Symptoms
- Cruise control inoperative or switches off
- Speed not held or fluctuating
- Usually no check engine light
Repair estimate
DifficultyMediumDIY possible
Parts and labour€50–450
Time0.5–2.5 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
cruise control servoservo cablevacuum hoseengine control module
Related codes
References: law.cornell.edu, en.wikipedia.org.