AutoCodes – GMC – P1649 2016 GMC Sierra

P1649 2016 GMC Sierra Code - Immobilizer Security Code Not Programmed

Quick Answer

When learning the security code, as well as the challenge and response sequence, the Engine Control Module (ECM) is placed in learn mode. Common causes include Perform Engine Control Module Immobilizer Learn Procedure, Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted. 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: P1649 2016 GMC Sierra indicates Immobilizer Security Code Not Programmed.
Common causes: Common causes include Perform Engine Control Module Immobilizer Learn Procedure, Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted.
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 206

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 Aug 17, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1649 2016 GMC Sierra Description

When learning the security code, as well as the challenge and response sequence, the Engine Control Module (ECM) is placed in learn mode. Once the security code and challenge/response are learned, learn mode will be exited when the engine is successfully started. The Diagnostic Trouble Code (DTC) will be set when the ECM has not learned a security code.

OBDII Code P1649 2016 GMC Sierra - Immobilizer Security Code Not Programmed - AutoCodes.com — P1649 2016 GMC Sierra Code - Immobilizer Security Code Not Programmed

What does this mean?

What are the Possible Causes of the DTC P1649 2016 GMC Sierra?

Perform Engine Control Module Immobilizer Learn Procedure
Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection

How to Fix the DTC P1649 2016 GMC Sierra?

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 P1649 2016 GMC Sierra 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 P1649 2016 GMC Sierra code?

Need more information on how to fix the P1649 2016 GMC Sierra 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 P1649 2016 GMC Sierra Code

1. What does the OBDII code P1649 on a 2016 GMC Sierra mean?

The code P1649 indicates that the immobilizer security code is not programmed correctly in the vehicle's system.

2. What are the common symptoms of the P1649 code in a 2016 GMC Sierra?

Common symptoms include the engine not starting, the security light flashing on the dashboard, and the vehicle going into anti-theft mode.

3. What are the possible causes of the P1649 code in a 2016 GMC Sierra?

The code may be triggered by issues with the key fob, a faulty immobilizer system, a dead battery in the key fob, or a mismatch between the key and the vehicle's security system.

4. How can I diagnose the P1649 code on my 2016 GMC Sierra?

Diagnosing this code typically involves checking the key fob battery, ensuring the key is programmed correctly, and verifying the immobilizer system's functionality.

5. Can I drive my 2016 GMC Sierra with the P1649 code?

If the vehicle is in anti-theft mode due to the P1649 code, it may not start or may stall while driving. It's recommended to address the issue promptly to avoid potential inconvenience.

6. How can I repair the P1649 code on my 2016 GMC Sierra?

Repairing this code often involves reprogramming the immobilizer system, replacing the key fob battery, or updating the vehicle's software to ensure proper communication between the key and the security system.

7. Can I reset the P1649 code on my 2016 GMC Sierra by disconnecting the battery?

While disconnecting the battery may reset the code temporarily, addressing the root cause of the issue is necessary to prevent the code from reoccurring.

8. Is it safe to attempt DIY repairs for the P1649 code on a 2016 GMC Sierra?

Depending on your automotive repair experience, you may be able to address simple causes like a key fob battery replacement. However, complex issues with the immobilizer system may require professional assistance.

9. Will the P1649 code on my 2016 GMC Sierra cause any long-term damage if left unrepaired?

Leaving the P1649 code unaddressed may lead to continued starting issues and potential inconvenience. It's advisable to resolve the problem promptly to ensure the vehicle's proper functionality.

10. How much can I expect to pay for repairing the P1649 code on a 2016 GMC Sierra?

The cost of repairing the P1649 code can vary based on the root cause of the issue and whether you choose DIY solutions or professional help. Factors like parts replacement and labor costs will affect the overall repair expenses.