Engine-CodesGMC – P0703 2018 GMC Sierra

P0703 2018 GMC Sierra Code - Brake Switch Signal Message Counter Incorrect

Quick Answer

The P0703 code on a 2018 GMC Sierra indicates that there is an issue with the brake switch signal message counter being incorrect. Common causes include Faulty brake switch, Wiring issues or short circuits, Malfunctioning transmission control module. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0703 2018 GMC Sierra indicates Brake Switch Signal Message Counter Incorrect.
Common causes
Common causes include Faulty brake switch, Wiring issues or short circuits, Malfunctioning transmission control module.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code P0703 2018 GMC Sierra Description

The P0703 code on a 2018 GMC Sierra indicates that there is an issue with the brake switch signal message counter being incorrect. The brake switch is a crucial component in the vehicle's braking system, as it signals to the vehicle's computer when the brakes are applied. This information is used by various systems in the vehicle to ensure proper operation, such as the transmission control module, cruise control system, and traction control system.

OBDII Code P0703 2018 GMC Sierra - Brake Switch Signal Message Counter Incorrect
P0703 2018 GMC Sierra Code - Brake Switch Signal Message Counter Incorrect

Common Causes of P0703 2018 GMC Sierra

  1. Faulty brake switch
  2. Wiring issues or short circuits
  3. Malfunctioning transmission control module
  4. Corrosion or damage to electrical connectors
  5. Software issues with the vehicle's computer systems

Symptoms of P0703 2018 GMC Sierra

  1. Harsh shifting or difficulty shifting gears
  2. Cruise control not engaging or disengaging properly
  3. Traction control warning light illuminated on the dashboard
  4. Vehicle not starting or shifting out of park

How to Fix P0703 2018 GMC Sierra

  1. Start by connecting a diagnostic scanner to the vehicle's OBD-II port to retrieve the trouble codes and confirm the P0703 code.
  2. Inspect the brake switch and wiring for any visible damage or corrosion. Replace the brake switch if necessary.
  3. Check the transmission control module for any signs of malfunction or software issues. Reset or reprogram the module as needed.
  4. Test the vehicle to ensure that the P0703 code no longer appears and that all systems are functioning properly.
  5. Clear the trouble codes from the vehicle's computer and reset any affected systems.

Cost to Fix P0703 2018 GMC Sierra

The typical repair costs for addressing a P0703 code on a 2018 GMC Sierra can range from $100 to $300, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that the actual cost may vary based on the location of the repair shop, the make and model of the vehicle, and the complexity of the repair. Additionally, diagnostic time and labor rates can impact the final cost, with hourly rates typically ranging from $80 to $150. It's recommended to obtain quotes from multiple repair shops to ensure a competitive price for the repair.

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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.

Frequently Asked Questions about P0703 2018 GMC Sierra Code

What does the P0703 code mean on a 2018 GMC Sierra?

The P0703 code indicates an issue with the brake switch signal, specifically an incorrect message counter being detected by the powertrain control module (PCM).

What are common symptoms of the P0703 code?

Symptoms include difficulty shifting gears, cruise control not functioning, reduced engine performance, or the check engine light illuminating.

What causes the P0703 code on a GMC Sierra?

Common causes include a faulty brake switch, damaged wiring or connectors in the brake switch circuit, or issues with the PCM.

Can a faulty brake switch trigger the P0703 code?

Yes, a malfunctioning brake switch is one of the most common causes of the P0703 code.

How can I diagnose the P0703 code?

Start by inspecting the brake switch and its wiring for damage or loose connections. Use a scan tool to monitor the brake switch signal and verify its operation.

Is it safe to drive with the P0703 code on a 2018 GMC Sierra?

It is not recommended as it may impact vehicle safety features like cruise control and proper gear shifting.

How do I fix the P0703 code?

Repairs may include replacing the brake switch, repairing or replacing damaged wiring, or addressing issues with the PCM.

Can the P0703 code affect the cruise control system?

Yes, the cruise control system relies on the brake switch signal, so this code can cause it to stop functioning.

Do I need a professional to fix the P0703 code?

While simple issues like a damaged brake switch can be fixed by someone with basic mechanical skills, complex wiring or PCM problems may require a professional diagnosis.

Will clearing the P0703 code with a scan tool fix the problem?

Clearing the code may temporarily turn off the check engine light, but the underlying issue must be repaired to prevent the code from returning.

Discuss the causes and fixes for P0703 2018 GMC Sierra OBDII Code

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