Engine-CodesGMC – P1677 GMC

P1677 GMC Code - Immobilizer Function Deactivated

Quick Answer

The P1677 GMC code indicates that the immobilizer function in the vehicle has been deactivated. Common causes include Faulty immobilizer system components, Issues with the key fob or key transponder, Wiring or electrical problems in the immobilizer system. 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
P1677 GMC indicates Immobilizer Function Deactivated.
Common causes
Common causes include Faulty immobilizer system components, Issues with the key fob or key transponder, Wiring or electrical problems in the immobilizer system.
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 10, 2024
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Code P1677 GMC Description

The P1677 GMC code indicates that the immobilizer function in the vehicle has been deactivated. The immobilizer is a security feature that prevents the engine from starting unless the correct key is used. When this function is deactivated, it can leave the vehicle vulnerable to theft as the engine can be started with any key, or in some cases, not start at all. This code is typically found in vehicles with advanced anti-theft systems.

OBDII Code P1677 GMC - Immobilizer Function Deactivated
P1677 GMC Code - Immobilizer Function Deactivated

Common Causes of P1677 GMC

  1. Faulty immobilizer system components
  2. Issues with the key fob or key transponder
  3. Wiring or electrical problems in the immobilizer system
  4. ECM communication issues with the immobilizer system
  5. Aftermarket modifications interfering with the immobilizer function

Symptoms of P1677 GMC

  1. Engine cranks but does not start
  2. Security light illuminated on the dashboard
  3. Engine starts and then immediately shuts off
  4. Inability to start the engine using the correct key

How to Fix P1677 GMC

  1. Check and replace the key fob battery
  2. Reset the immobilizer system by disconnecting the battery for a few minutes
  3. Inspect and repair any damaged wiring or electrical connections related to the immobilizer system
  4. Use a diagnostic scanner to reset the immobilizer system and reprogram any necessary components
  5. If necessary, replace the immobilizer system components such as the key transponder or ECM

Cost to Fix P1677 GMC

The typical repair costs for addressing the P1677 GMC code can range from $100 to $500, depending on the specific cause of the issue and the extent of repairs needed. This estimate includes parts and labor, but the final cost may vary based on the location, vehicle make and model, and the hourly labor rates of the auto repair shop. It is advisable to consult with a professional technician to get an accurate estimate for your specific vehicle.

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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.

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