AutoCodes – GMC – P1649 GMC

P1649 GMC 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 GMC 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 1,698

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

What does this mean?

What are the Possible Causes of the DTC P1649 GMC?

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 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 P1649 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 P1649 GMC code?

Need more information on how to fix the P1649 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1649 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P1649 2014 GMC Sierra — Immobilizer Security Code Not Programmed
P1649 2015 GMC Sierra — Immobilizer Security Code Not Programmed
P1649 2016 GMC Sierra — Immobilizer Security Code Not Programmed
P1649 2017 GMC Sierra — Immobilizer Security Code Not Programmed
P1649 2018 GMC Sierra — Immobilizer Security Code Not Programmed

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 GMC Code

1. What are the common symptoms of OBDII code P1649 GMC (Immobilizer Security Code Not Programmed)?

- Common symptoms include the vehicle not starting, the engine stalling, and the immobilizer warning light illuminating on the dashboard.

2. What does the OBDII code P1649 GMC indicate?

- The code P1649 indicates that the immobilizer security code has not been programmed into the vehicle's system, preventing the engine from starting.

3. What are the possible causes of OBDII code P1649 GMC?

- The possible causes include a faulty immobilizer system, a disconnected or damaged immobilizer module, or issues with the key fob or key programming.

4. How can I repair OBDII code P1649 GMC?

- To repair the code P1649, you may need to reprogram the immobilizer system using a compatible diagnostic scanner, check and replace any faulty components, or reset the system following the manufacturer's instructions.

5. Can I fix OBDII code P1649 GMC at home?

- While some basic troubleshooting steps can be done at home, resolving this code may require specialized tools and knowledge. It is recommended to consult a professional mechanic for accurate diagnosis and repair.

6. Is it safe to drive with OBDII code P1649 GMC present?

- It is not recommended to drive the vehicle with the P1649 code active, as it may lead to unexpected stalling or starting issues, potentially leaving you stranded.

7. How much does it typically cost to repair OBDII code P1649 GMC?

- The cost of repairing this code can vary depending on the exact cause of the issue, the labor rates in your area, and the parts needed. It is advisable to get a diagnostic assessment from a qualified technician for an accurate estimate.

8. Can a dead battery cause OBDII code P1649 GMC to appear?

- Yes, a dead or disconnected battery can sometimes trigger the P1649 code due to a loss of power to the immobilizer system. Ensuring the battery is charged and properly connected is a good first step in troubleshooting.

9. How long does it take to diagnose OBDII code P1649 GMC?

- The diagnosis time can vary depending on the complexity of the issue and the availability of diagnostic tools. A skilled mechanic should be able to diagnose the problem within an hour or two in most cases.

10. Are there any preventive measures to avoid OBDII code P1649 GMC?

- Regular maintenance, such as checking the battery condition, ensuring proper key programming, and addressing any warning lights promptly, can help prevent issues like code P1649 from occurring.