P0596
Cruise Control Servo Control Circuit High
Cruise control
Generic OBD-II
Low
What it means
P0596 means the module driving the cruise control servo detected a higher-than-expected voltage on the servo control circuit, usually from a short to power or an open in the wiring. The servo is what moves the throttle to hold your set speed, so cruise control may not engage. It's a comfort-feature fault and doesn't affect normal driving.
Low
Can I keep driving? Safe to drive — only cruise control is affected; normal driving, braking, and acceleration are unchanged.
Common symptoms
What you'll notice
- Check-engine light on
- Cruise control won't engage
- Cruise control can't set or hold a speed
- No effect on normal driving
Common causes
Most likely first
- Faulty cruise control servoLikely
- Short to voltage in the servo control wiringCommon
- Loose or corroded connector at the servoCommon
- Failed engine/cruise control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the cruise control servo connector and wiring — a 'high' circuit code usually points to a short to power or an open in the control line.
- Check the servo control wiring for shorts to a voltage source and repair as needed.
- Test the servo's resistance against spec and replace it if out of range.
- If wiring and servo are good, test the controlling module. Clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P0596?+
Yes. The fault is confined to the cruise control servo circuit, so the car drives normally. You just won't have reliable cruise control until it's repaired.
Can I just clear P0596?+
You can, but it will return once the module again detects the high voltage on the servo control circuit. Fix the wiring or servo to clear it for good.
Related codes
Often seen with P0596
Read & clear P0596 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX