AutoCodes – Generic – P1649

P1649 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 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 19,771

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

What does this mean?

What are the Possible Causes of the DTC P1649?

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?

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 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 code?

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Need Help with the Code?

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Information for Specific Makes

P1649 Audi — CAN Data Bus ABS No Signal
P1649 Buick — Immobilizer Security Code Not Programmed
P1649 Cadillac — Immobilizer Security Code Not Programmed
P1649 Chevrolet — Immobilizer Security Code Not Programmed
P1649 GMC — Immobilizer Security Code Not Programmed
P1649 Volkswagen — CAN Data Bus ABS No Signal

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.