HomeTrouble CodesP0595

P0595 — Cruise Control Servo Control Circuit Low

Generic OBD-II · all makesPowertrain (engine & transmission)

P0595 indicates the vehicle's computer has detected a lower-than-expected voltage signal in the cruise control servo control circuit. This fault typically prevents the cruise control system from engaging or maintaining a set speed. The issue usually lies within the servo actuator, wiring, or electrical connections rather than the main computer.

Symptoms

What causes it — most likely first

1. Faulty Cruise Control Servo Actuator

The electric motor responsible for adjusting throttle position may have an internal short or mechanical failure.

2. Damaged Wiring Harness

Wires in the servo circuit may be frayed, burnt, or shorted to ground near the engine bay.

3. Corroded Electrical Connectors

Moisture or oxidation at the servo connector can cause high resistance or low voltage signals.

4. Blown Cruise Control Fuse

A protective fuse in the power circuit may have blown due to a surge or short condition.

5. Faulty Cruise Control Switch

The steering wheel or stalk switch may have internal resistance issues affecting the control circuit.

6. PCM Control Module Failure

Internal driver circuit failure within the computer is rare and should only be considered after all external components are verified.

How it's diagnosed

  1. Inspect the cruise control fuse and replace if blown.
  2. Visually examine wiring harnesses and connectors near the servo actuator for damage.
  3. Measure voltage and resistance at the servo connector against manufacturer specifications.
  4. Check continuity between the servo connector and the PCM pins to rule out open circuits.
  5. Test the brake pedal position switch for proper operation and signal output.
  6. Substitute known-good components to isolate the fault before considering module replacement.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Does this code mean I need a new computer?

No, PCM failure is rare for this code; the servo actuator or wiring is the usual cause.

Is it safe to drive with this code?

Yes, the vehicle drives normally, but the cruise control function will be disabled.

Will clearing the code fix the problem?

No, the underlying electrical fault must be repaired or the code will return.