P0525: Cruise Control Servo Control Circuit Range/Performance
What to do
Driveable; cruise control will be unreliable or will not hold speed. Not a safety issue provided you are aware it may disengage.
What this code means
The cruise control servo is not holding the position commanded. On older vacuum-operated systems the servo pulls the throttle cable against a vacuum diaphragm, and a leaking diaphragm or perished vacuum hose leaves it unable to hold — the classic symptom being cruise control that engages and then slowly bleeds off speed on a climb.
Electronic systems have no servo at all and operate the drive-by-wire throttle directly, so this code appears mostly on older vehicles.
Likely causes
Start here
- Leaking cruise control servo diaphragm · moderate
- Disconnected or leaking vacuum hose · easy
- Faulty cruise control servo · moderate
Less common
- Stretched or binding throttle cable · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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