P0595 — Cruise Control Servo Control Circuit Low #

The code description may vary depending on the vehicle manufacturer.

• “Cruise Control Servo Control Circuit Low” (Generic/SAE)
• “Cruise Control Servo Circuit Low Input” (Ford)
• “Cruise Control Actuator Signal Low” (Hyundai/Kia)
• “Speed Control Servo Voltage Low” (Chrysler/Jeep/Dodge)

Summary of code P0595 #

DTC P0595 indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the cruise control servo control circuit. The cruise control servo is an actuator—a device that physically manipulates the throttle to maintain a set speed when cruise control is engaged. When the circuit controlling this servo registers abnormally low voltage, it can disrupt cruise control operation. This code is typically triggered by electrical issues such as wiring faults, a failing servo, or a malfunctioning control module. While the car’s primary drivability is usually unaffected, cruise control may not operate as intended.

Common symptoms for code P0595 #

When P0595 is stored, you might notice issues with your vehicle’s cruise control system. Sometimes, the symptoms are subtle and only appear when trying to activate or use cruise control. In other cases, dashboard warning lights may illuminate, but the vehicle otherwise drives normally.

• Cruise control does not engage
• Cruise control disengages unexpectedly
• Check Engine Light (CEL) or Service Engine Soon light is on
• Warning message related to cruise control system
• Intermittent or unreliable cruise control function

Most common causes of P0595 #

This code is almost always the result of an electrical fault in the cruise control servo circuit. Here are the most frequent causes, listed in order of likelihood:

1. Faulty cruise control servo motor (actuator is internally open or shorted)
2. Damaged or corroded wiring/connectors in the servo control circuit
3. Faulty PCM (rare, but possible if all else checks out)
4. Blown fuse or relay related to the cruise control system
5. Poor ground connection at the servo or PCM

Step-by-step diagnosis for code P0595 #

Diagnosing P0595 requires a methodical approach, starting with basic visual checks and moving towards more technical electrical testing. If you’re comfortable with a digital multimeter and have access to wiring diagrams, you can perform many of these steps yourself.

• 1. Verify the code: Use a scan tool to confirm P0595 is active and note any other related codes.
• 2. Inspect fuses and relays: Check all fuses and relays linked to the cruise control system for continuity and correct operation.
• 3. Visual inspection: Examine the cruise control servo and its wiring harness for signs of damage, corrosion, or loose connections.
• 4. Check voltage: With the ignition on, use a multimeter to measure voltage at the servo connector. Reference OEM wiring diagrams for correct pin locations and expected values.
• 5. Test ground circuits: Confirm that the servo’s ground is intact and has minimal resistance.
• 6. Servo actuator bench test: If accessible, disconnect the servo and bench test it per OEM procedures to verify functionality.
• 7. PCM check: If all wiring and the servo test good, suspect a fault in the PCM and test/replace as per manufacturer instructions.

Possible repairs for code P0595 #

The repair will depend on the cause found during diagnosis. Addressing P0595 usually restores full cruise control operation. Here are the most common fixes:

• Replace faulty cruise control servo/actuator
• Repair or replace damaged wiring/connectors
• Clean corroded connections and re-secure loose terminals
• Replace blown fuse or faulty relay
• Repair or improve ground connections
• Replace PCM (only after all other possibilities have been eliminated and confirmed via OEM testing)

Is it safe to drive with code P0595? #

Yes, you can usually drive with code P0595 active, but with limitations. This code does not affect the core safety or drivability of your vehicle—only the cruise control system is impacted. However, you should not rely on cruise control until the issue is fixed, and you should address the problem soon to restore the feature. If other codes are present or you notice additional symptoms, have the vehicle inspected promptly.

Vehicles most commonly affected by code P0595 #

While P0595 is a generic OBD-II code, it tends to appear most often on vehicles where the cruise control servo is externally mounted and uses a dedicated circuit. The following makes and models are frequently associated with this code:

• Ford: F-150, Focus, Escape
• Hyundai/Kia: Sonata, Santa Fe, Elantra, Sorento
• Chrysler/Jeep/Dodge: Grand Cherokee, Ram, Pacifica, Charger
• Honda: Accord, Civic (rare, but possible on models with cable-actuated cruise)
• Nissan: Frontier, Xterra, Pathfinder

Common mistakes & best practices with code P0595 #

It’s surprisingly easy to misdiagnose P0595, especially if you skip steps or overlook simple issues. Here’s how to avoid common pitfalls and ensure an accurate repair:

• Replacing the servo without checking wiring: Always inspect and test the circuit before replacing parts.
• Ignoring ground connections: A bad ground can mimic a servo or PCM failure.
• Clearing the code without addressing the cause: The code will return if the root problem remains.
• Not checking related fuses/relays: A simple blown fuse can be overlooked.
• Assuming PCM failure too early: PCM faults are rare; exhaust all other possibilities first.

FAQ for code P0595 #

Got questions about P0595? Here are quick answers to some common concerns:

• Q: Will my car pass inspection with P0595 stored?
  A: In most regions, any active “Check Engine” light or stored DTC will cause a failed emissions inspection—even if the issue is only with cruise control.
• Q: Can I fix P0595 myself?
  A: If you’re comfortable with basic electrical troubleshooting and have access to wiring diagrams, you might be able to address wiring or fuse issues yourself. Servo or PCM replacement may require professional tools and procedures.