Engine-CodesGeneric – P1597

P1597 Code - Speed Control Switch Always Low

Quick Answer

The P1597 diagnostic trouble code (DTC) indicates that the speed control switch in the vehicle is always in a low state. Common causes include Faulty speed control switch, Wiring issues or loose connections in the cruise control system, Defective cruise control module. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means
P1597 indicates Speed Control Switch Always Low.
Common causes
Common causes include Faulty speed control switch, Wiring issues or loose connections in the cruise control system, Defective cruise control module.
Severity
Low - monitor the vehicle and repair when practical.
Can I drive?
The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P1597 Description

The P1597 diagnostic trouble code (DTC) indicates that the speed control switch in the vehicle is always in a low state. This means that the signal being sent from the speed control switch to the engine control module (ECM) is consistently registering as low, regardless of the actual position of the switch. The speed control switch is a crucial component of the vehicle's cruise control system, which allows the driver to set and maintain a desired speed without constantly having to apply pressure to the accelerator pedal.

OBDII Code P1597 - Speed Control Switch Always Low
P1597 Code - Speed Control Switch Always Low

Common Causes of P1597

  1. Faulty speed control switch
  2. Wiring issues or loose connections in the cruise control system
  3. Defective cruise control module
  4. Malfunctioning engine control module (ECM)
  5. Corrosion or damage to the speed control switch components

Symptoms of P1597

  1. Inability to engage or maintain cruise control
  2. Difficulty setting a desired speed using the cruise control system
  3. Illumination of the cruise control warning light on the dashboard
  4. Erratic behavior of the vehicle's speed control system

How to Fix P1597

  1. Begin by conducting a thorough diagnosis of the cruise control system to pinpoint the exact cause of the speed control switch always being low.
  2. Inspect the speed control switch for any visible damage or signs of wear. Replace the switch if necessary.
  3. Check the wiring and connections in the cruise control system for any faults or loose connections. Repair or replace any damaged components.
  4. Test the cruise control module and ECM to ensure they are functioning correctly. Replace any faulty modules as needed.
  5. Clear the DTC from the ECM's memory and perform a test drive to verify that the cruise control system is operating as intended.

Cost to Fix P1597

The cost of repairing a P1597 code can vary depending on the specific cause of the issue and the labor rates in your area. Typically, replacing a faulty speed control switch or repairing wiring issues can range from $100 to $300. If the cruise control module or ECM needs to be replaced, the cost can increase significantly, potentially reaching up to $500 or more. It is advisable to consult with a qualified mechanic or repair shop to get an accurate estimate based on your vehicle's make and model. Remember that diagnostic time and labor rates can also affect the final cost of the repair.

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Code P1597 Information for Specific Makes

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.

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