AutoCodes – Buick – P1631 Buick

P1631 Buick Code - Theft Deterrent Start Enable Signal Not Correct

Quick Answer

The Body Control Module (BCM) sends the pre-release information to the Engine Control Module (ECM) via the serial data circuit. Common causes include Perform security relearn procedure, Faulty Ignition switch assembly, Ignition switch assembly 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: P1631 Buick indicates Theft Deterrent Start Enable Signal Not Correct.
Common causes: Common causes include Perform security relearn procedure, Faulty Ignition switch assembly, Ignition switch assembly 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 8,159

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
Tech Notes
Cost to Diagnose
Comments
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Code P1631 Buick Description

The Body Control Module (BCM) sends the pre-release information to the Engine Control Module (ECM) via the serial data circuit. The ECM then sends a challenge to the BCM. Both the ECM and BCM perform a calculation on this challenge. If the calculated response from the BCM equals the calculation performed by the ECM, the ECM will allow the vehicle to start. The BCM follows this action by sending the remaining immobilizer data to the ECM. If the immobilizer data sent by the BCM matches that stored by the ECM, the ECM will allow the engine to remain running. The Diagnostic Trouble Code (DTC) will be set if the ECM receives incorrect immobilizer data from the BCM.

OBDII Code P1631 Buick - Theft Deterrent Start Enable Signal Not Correct - AutoCodes.com — P1631 Buick Code - Theft Deterrent Start Enable Signal Not Correct

What does this mean?

What are the Possible Causes of the DTC P1631 Buick?

Perform security relearn procedure
Faulty Ignition switch assembly
Ignition switch assembly harness is open or shorted
Ignition switch assembly circuit poor electrical connection

How to Fix the DTC P1631 Buick?

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 does this mean?

Code Tech Notes

Security Relearn Procedure:

-Insert the key, attempt to start the vehicle, and leave the key in the ON position.
In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-When the Security light goes OFF, turn the ignition to the OFF position.
-Leave ignition OFF for 20 Seconds.
-Attempt to start the vehicle again and leave the key in the ON position.
-In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-Turn the ignition to the OFF position for 20 Seconds.
-Attempt to start the vehicle again and leave the key in the ON position.
-In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-Once this entire procedure has been completed (three times) your vehicle will start on the fourth attempt.

Note: Some vehicles perform the relearn in a different sequence. You may notice your security light, battery light, and abs light will alternate. Once the security light is left out of the sequence that is considered one step. Repeat the procedure two more times and on the fourth time, your vehicle will start.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1631 Buick 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.

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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.