Theft Deterrent Start Enable Signal Not Correct
Table of contents
P1631 BUICK Possible Causes
- Perform security relearn procedure
- Faulty Ignition switch assembly
- Ignition switch assembly harness is open or shorted
- Ignition switch assembly circuit poor electrical connection
How do I fix code P1631 BUICK?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- Security Relearn Procedure:
- -Insert 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.
Cost of diagnosing the P1631 BUICK code
The cost of diagnosing the P1631 BUICK code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P1631 BUICK Description
The class 2 serial data circuit is used in order to communicate between the Powertrain Control Module (PCM) and the Vehicle Theft Deterrent (VTD) Body Control Module (BCM) systems.
When the Passlock portion of the VTD system has sensed the proper operation of the ignition switch and lock, or determined that the switch and lock have not been tampered with, the BCM transmits a password to the PCM. Fuel delivery is enabled if this password matches the password stored in the modules memory. If a component in the theft deterrent system has been replaced, the modules need to relearn the password of the new components. If the relearn procedure was not performed, this DTC will set.
If a VTD failure occurs during an ignition cycle that the PCM has enabled fuel, then the BCM will enter a fail-safe mode: Fail Enable VTD System Failure with Fuel Enabled. The BCM remains in Fail Enable Mode, for the current and future ignition cycles, until the fault is corrected and a valid password is received, or until battery power is removed. If the battery is disconnected or the codes are cleared, the vehicle will lose its Fail Enable status and will not start until the fault is corrected, the 10-minute timer expires, and the PCM receives the correct fuel delivery password.