Is it safe to drive with this code?

In most cases, the vehicle remains safe to drive as P0594 typically only affects cruise control function. However, if a blown fuse is the cause, other minor electrical systems may be affected. If you notice unusual throttle behaviour or the engine racing, stop using the vehicle until it can be inspected—see our disclaimer for guidance on driving with faults.

P0594 may affect your MOT outcome if the malfunction indicator lamp (engine warning light) is illuminated at the time of test. The cruise control itself is not part of the MOT inspection, but an illuminated warning light can result in a fail—refer to our disclaimer for details on MOT implications.

Roughly how much does it cost to fix?

Repair costs vary widely depending on the underlying cause. A blown fuse or simple wiring repair may fall into the low two-figure range, whilst replacing vacuum hoses or connectors typically sits in the low three-figure band. If the cruise control servo unit itself has failed, costs can reach the mid three-figure range, with higher charges at main dealers compared to independent garages.

Can I simply ignore this code if I don't use cruise control?

Whilst the cruise control may not be essential, leaving the code unresolved can mask new faults from appearing and may indicate broader electrical issues. Additionally, an active fault code can prevent the vehicle from passing emissions testing in some cases, so it's often worth addressing.

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← All fault codes | Electrical & Sensors

P0594

Powertrain

Cruise Control Servo Control Circuit /Open

The engine control module has identified an open circuit or general electrical fault within the cruise control servo control system, which typically prevents the cruise control from functioning properly.

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ⓘ Information only. This page provides general educational information about fault code P0594. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P0594 mean?

P0594 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cruise Control Servo Control Circuit /Open.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

About Electrical & Sensors codes

Codes in the Electrical & Sensors category.

P0594 is one of 4,010 codes in this category. Browse all Electrical & Sensors codes →

What we know about P0594 specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P0594.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

•your vehicle's own service manual or manufacturer-specific technical bulletins
•a qualified mechanic with a manufacturer-level diagnostic tool
•a marque specialist familiar with your make and model

Codes nearby

Codes adjacent to P0594 in the P-code series. Many fault codes appear together with their neighbours because they relate to the same circuit or component.

P0591 Cruise Control Multi-Function Input B Circuit Range/Performance

P0592 Cruise Control Multi-Function Input B Circuit Low

P0593 Cruise Control Multi-Function Input B Circuit High

P0595 Cruise Control Servo Control Circuit Low

P0596 Cruise Control Servo Control Circuit High

P0597 Thermostat Heater Control Circuit Open

Other Electrical & Sensors codes

Other fault codes in the same system as P0594. The ones with detailed guides have plain-English explanations, symptoms, causes, and diagnostic steps.

B1257

Air Temperature External Sensor Circuit Short To Ground Detailed guide

B1363

DBPT Circuit Short To Ground Detailed guide

B2100

Ignition Run/Start Input Circuit Performance Detailed guide

C2000

Steering Angle Sensor Not Calibrated Detailed guide

P0030

HO2S Heater Control Circuit (Bank 1 Sensor 1) Detailed guide

P0031

Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1) Detailed guide

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P0594 can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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