AutoCodes – Generic – P0594

P0594 Code - Cruise Control Servo Control Circuit/Open

Quick Answer

The Engine Control Module (ECM) monitors the Cruise Control Servo. Common causes include Faulty Servo Motor, Servo Motor harness is open or shorted, Servo Motor circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0594 indicates Cruise Control Servo Control Circuit/Open.
Common causes: Common causes include Faulty Servo Motor, Servo Motor harness is open or shorted, Servo Motor circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 11,477

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 28, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0594 Description

The Engine Control Module (ECM) monitors the Cruise Control Servo. The ECM sets the OBDII code when the Cruise Control Servo is not to factory specifications.

OBDII Code P0594 - Cruise Control Servo Control Circuit/Open - AutoCodes.com — P0594 Code - Cruise Control Servo Control Circuit/Open

What does this mean?

What are the Possible Causes of the DTC P0594?

Faulty Servo Motor
Servo Motor harness is open or shorted
Servo Motor circuit poor electrical connection

How to Fix the DTC P0594?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0594 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0594 code?

Need more information on how to fix the P0594 code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Makes

P0594 Chrysler — Speed Control Servo Circuit
P0594 Mazda — Speed Control Servo Control Circuit Open
P0594 Mitsubishi — Speed Control Servo Power Relay Circuit

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.