Engine-CodesCadillac – P1631 Cadillac

P1631 Cadillac Code - Theft Deterrent Start Enable Signal Not Correct

Quick Answer

The P1631 Cadillac code indicates that there is a problem with the Theft Deterrent Start Enable Signal in the vehicle. Common causes include Faulty ignition switch, Malfunctioning key fob, Wiring issues in the Theft Deterrent System. 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 Cadillac indicates Theft Deterrent Start Enable Signal Not Correct.
Common causes
Common causes include Faulty ignition switch, Malfunctioning key fob, Wiring issues in the Theft Deterrent System.
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.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P1631 Cadillac Description

The P1631 Cadillac code indicates that there is a problem with the Theft Deterrent Start Enable Signal in the vehicle. This system is designed to prevent unauthorized individuals from starting the vehicle, providing an added layer of security. When this signal is not correct, it can lead to issues with starting the vehicle or even prevent it from starting altogether.

OBDII Code P1631 Cadillac - Theft Deterrent Start Enable Signal Not Correct
P1631 Cadillac Code - Theft Deterrent Start Enable Signal Not Correct

Common Causes of P1631 Cadillac

  1. Faulty ignition switch
  2. Malfunctioning key fob
  3. Wiring issues in the Theft Deterrent System
  4. Faulty ECM or PCM
  5. Dead or weak car battery

Symptoms of P1631 Cadillac

  1. Engine cranks but does not start
  2. Security light flashing on the dashboard
  3. Inability to start the vehicle with the correct key
  4. Engine starting and then immediately stalling
  5. Loss of power while driving

How to Fix P1631 Cadillac

  1. Begin by checking the battery voltage and ensuring it is in good condition.
  2. Inspect the wiring in the Theft Deterrent System for any signs of damage or corrosion.
  3. Check the ignition switch and key fob for proper operation or replace if necessary.
  4. Reset the Theft Deterrent System by disconnecting the battery for a few minutes.
  5. If the issue persists, consult a professional mechanic or dealership for further diagnosis and potential replacement of the ECM.

Cost to Fix P1631 Cadillac

The cost estimate for repairing a P1631 Cadillac code can vary depending on the specific cause of the issue. Generally, the cost can range from $100 to $500 for parts and labor. Keep in mind that these are rough estimates, and actual costs may vary based on the location, vehicle make and model, and the mechanic's hourly rates. It is advisable to get a detailed quote from a trusted auto repair shop before proceeding with the repair.

Tech Notes for P1631 Cadillac

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.

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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 P1631 Cadillac Code

1. What are the common symptoms of OBDII code P1631 on a Cadillac related to the Theft Deterrent Start Enable Signal Not Correct issue?

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

2. What are the possible causes of OBDII code P1631 on a Cadillac?

- Possible causes may include a faulty ignition switch, issues with the key or key cylinder, problems with the Body Control Module (BCM), or a wiring issue.

3. How can I diagnose the OBDII code P1631 on my Cadillac?

- To diagnose this code, it is recommended to perform a thorough inspection of the ignition system, check for any damaged wiring, and use a diagnostic scanner to retrieve additional trouble codes.

4. Can I still drive my Cadillac with the OBDII code P1631 present?

- It is not recommended to drive your Cadillac with the P1631 code present, as it may lead to starting issues or the vehicle going into theft deterrent mode unexpectedly.

5. How can I reset the OBDII code P1631 on my Cadillac?

- To reset the code, you can try disconnecting the battery for a few minutes or using a diagnostic scanner to clear the code after addressing the underlying issue.

6. Will disconnecting the battery reset the OBDII code P1631 on my Cadillac?

- Disconnecting the battery may temporarily clear the code, but it is important to address the root cause of the issue to prevent it from reoccurring.

7. Is it safe to attempt to repair the OBDII code P1631 on my Cadillac myself?

- While some basic troubleshooting steps can be taken, it is recommended to consult a professional mechanic or dealership for a proper diagnosis and repair to ensure safety and effectiveness.

8. Are there any common repair tips for fixing the OBDII code P1631 on a Cadillac?

- Common repair tips include checking and replacing the ignition switch, inspecting the key and key cylinder for damage, and ensuring all wiring connections are secure and free of corrosion.

9. How much can I expect to pay to repair the OBDII code P1631 on my Cadillac?

- The cost of repairing this code can vary depending on the root cause of the issue, but it is advisable to budget for diagnostic fees, parts replacement, and labor costs.

10. Can the OBDII code P1631 on a Cadillac be a recurring issue?

- If the underlying cause of the code is not properly addressed, it is possible for the P1631 code to reoccur, leading to starting problems and potential theft deterrent system malfunctions.

Discuss the causes and fixes for P1631 Cadillac OBDII Code

  • My 2005 CTS HAS A U0100 CODE I CAN'T FIND ANYTHING OUT ABOUT IT. I HAVE TO START IT WITH A JUMPER SEVERAL TIMES A WEEK AND RESET THE COMPUTER. IT'S PART OF THE ANTI-THEFT SYSTEM. IS THERE ANY WAY TO COMPLETELY DISABLE THIS GARBAGE.PLEASE LET ME KNOW.

  • So you have both codes P1631 and U0100? what is the engine size of your Cadillac? let me check if I can find more information.

    U0100 CADILLAC - Lost Communication With Engine Control Module
    Read more: https://www.autocodes.com/u...

  • It has a u0100 and a p0700 code, evidently, the ECM is not comunicating with the TCM properly. It is a 3.6L V6. I believe that I have isolated the problem to the TCM connector, it was wet. I disconnected it and cleaned it and sprayed it with WD-40 and fixed the moisture problem and it has not happened again, so far . Thanks.