AutoCodes – GMC – P1679 GMC

P1679 GMC Code - Immobilizer Environment Identification Failed

Quick Answer

The Engine Control Module (ECM), the Powertrain Interface Module (PIM), and the Body Control Module (BCM) are integral part of the vehicle theft deterrent system. Common causes include Deterrent key not programmed to vheicle, Faulty Deterrent key, Fualty ignition switch. 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: P1679 GMC indicates Immobilizer Environment Identification Failed.
Common causes: Common causes include Deterrent key not programmed to vheicle, Faulty Deterrent key, Fualty ignition switch.
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.

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Code Popularity 4,460

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 08, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1679 GMC Description

The Engine Control Module (ECM), the Powertrain Interface Module (PIM), and the Body Control Module (BCM) are integral part of the vehicle theft deterrent system. The theft deterrent system authenticates the security code programmed into each of these modules to prevent unauthorized vehicle operation. This authentication process includes the following steps:
1.When the ignition is turned ON or the door is unlocked by remote key the BCM and the key exchange security data to verify the correct key is used.
2.Once the correct key has been confirmed and the ignition is turned ON, the PIM and BCM exchange data to confirm the correct BCM and PIM is being used.
3.Once the correct key, BCM, and PIM is confirmed, the PIM and ECM exchange data to allow the vehicle to start.
4.The data exchange processes conducted use various encrypted data exchanges between each of the devices.

OBDII Code P1679 GMC - Immobilizer Environment Identification Failed - AutoCodes.com — P1679 GMC Code - Immobilizer Environment Identification Failed

What does this mean?

What are the Possible Causes of the DTC P1679 GMC?

Deterrent key not programmed to vheicle
Faulty Deterrent key
Fualty ignition switch
Poor electrical connection for Deterrent circuit components

How to Fix the DTC P1679 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1679 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1679 GMC code?

Need more information on how to fix the P1679 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P1679 GMC Code

1. What does the OBDII code P1679 mean on a GMC vehicle?

P1679 indicates that the immobilizer system failed to identify the environment, preventing proper communication between the vehicle's security system and the engine control module (ECM).

2. What are the common symptoms of code P1679 on a GMC?

Symptoms may include failure to start the vehicle, immobilizer warning light activation, and loss of communication between the key fob and the vehicle's security system.

3. What causes the P1679 code to appear on a GMC?

Common causes include a faulty immobilizer control unit, damaged key fob, wiring issues, or a malfunction in the ECM.

4. Can a dead key fob battery trigger the P1679 code?

Yes, a dead or weak key fob battery can prevent proper communication with the immobilizer system, potentially triggering this code.

5. How can you fix code P1679 on a GMC vehicle?

Repairs may involve reprogramming the immobilizer system, replacing the key fob, fixing wiring issues, or addressing problems within the ECM.

6. Is the P1679 code specific to GMC vehicles?

No, while P1679 is common for GMC vehicles, it can appear in other makes and models with similar immobilizer systems.

7. Can you clear the P1679 code without fixing the issue?

Clearing the code without addressing the underlying problem may only temporarily remove it, and the issue will likely recur.

8. Does the P1679 code prevent the vehicle from starting?

Yes, this code often results in a no-start condition due to immobilizer system failure.

9. Can a broken or damaged key fob cause the P1679 code?

Yes, a damaged or unprogrammed key fob may fail to communicate with the immobilizer system, leading to this error.

10. Do you need a professional to fix the P1679 code on a GMC?

While some fixes, like replacing a key fob battery, can be done by the owner, diagnosing and repairing wiring or ECU issues typically requires professional assistance.