OBD Guide

P0594

Cruise Control Servo Control Circuit/Open

P0594 is an OBD-II diagnostic trouble code meaning: Cruise Control Servo Control Circuit/Open. Common causes: broken wire in the servo control circuit, malfunction (winding break) of the actuator/servo drive. Estimated repair cost: $33–167.

Severity
Low
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Cruise control doesn't work at all
  • Check Engine Light Illuminates
  • No response to cruise control activation
  • Cruise control indicator may turn on but speed is not maintained

Causes

  • Broken wire in the servo control circuit
  • Malfunction (winding break) of the actuator/servo drive
  • Oxidation or damage to the servo connector
  • Faulty servo relay or fuse
  • Internal malfunction of the cruise control ECU

How to Fix

  1. Find the location of the cruise control servo according to the car diagram
  2. Check servo circuit fuse
  3. Measure the resistance of the actuator winding (standard: 20–100 Ohms depending on the type)
  4. Check the wires and connector for breaks and oxidation
  5. Check the presence of a control signal from the computer when activating cruise control
  6. Replace the servo or repair the wiring if a fault is detected

Related codes

Error P0594 by Vehicle Brand

FAQ

What does the P0594 code mean?

P0594 is an OBD-II diagnostic trouble code that indicates: Cruise Control Servo Control Circuit/Open

What causes a P0594 error code?

The most common causes of P0594 include: Broken wire in the servo control circuit; Malfunction (winding break) of the actuator/servo drive; Oxidation or damage to the servo connector; Faulty servo relay or fuse.

How do I fix a P0594 diagnostic trouble code?

To fix P0594: Find the location of the cruise control servo according to the car diagram. Check servo circuit fuse. Measure the resistance of the actuator winding (standard: 20–100 Ohms depending on the type). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0594?

Yes, but get it checked soon

How much does it cost to fix P0594?

The estimated repair cost for P0594 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat