Alarm goes off all by itself every day around the same time

ONESUNNY1

MEMBER
2005 CHEVROLET TAHOE
5.7L
V8
4WD
AUTOMATIC
170,000 MILES

Nobody is near the vehicle, nobody is holding a key fob, and all the doors are closed and locked. We even tried locking all of the doors manually with the key to keep the alarm from turning on, it still happened. Is there a way to disconnect or disable the alarm?

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,336 POSTS

Hi,

I have a feeling there may be an issue with the alarm module. It would set a code if there is. What I want to try first is to reprogram the theft deterrent system. There are two ways to do it. One is with a scan too and one without. If you do the one without a scan tool, it will take over 30 minutes. However, it will work.

Here are the directions for both. Take a look through this and try it to see if it helps stop the problem.

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2005 Chevy Truck Tahoe 4WD V8-5.3L VIN T
Programming Theft Deterrent System Components
Vehicle Accessories and Optional Equipment Antitheft and Alarm Systems Service and Repair Procedures Programming Theft Deterrent System Components
PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS
PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS

PROGRAMMING REPLACEMENT PASSLOCK(TM) SENSOR, BCM, OR PCM

IMPORTANT:
- The body control module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See Body Control Module (BCM) Programming/RPO Configuration.
- If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn Passlock(TM) sensor data code immediately. The existing PCM, however, must learn the new fuel continue password when the BCM is replaced.
- If replacing a powertrain control module (PCM) with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicles password.

CONDITIONS
Use this procedure after replacing:
- Passlock Sensor
- BCM
- PCM

LEARN PROCEDURES
There are 2 available methods to perform the programming procedure:
- A 10 minute procedure which requires a Tech 2 and a techline terminal.
- A 30 minute procedure which does not require the use of any tools.

10-MINUTE LEARN PROCEDURE
1. Connect the Tech 2 to the vehicle.
2. Select "Request Information" under "Service Programming".
3. Disconnect the Tech 2 from the vehicle and connect it to a techline terminal.
4. On the techline terminal, select "Theft Module Re-Learn" under "Service Programming".
5. Disconnect the Tech 2 from the techline terminal and connect it to the vehicle.
6. Turn ON the ignition, with the engine OFF.
7. Select "Program ECU" under "Service Programming".
8. Attempt to start the engine, then release the key to ON, vehicle will not start.
9. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK.
10. Turn OFF the ignition, and wait 5 seconds.
11. Start the engine; the vehicle has now learned the password.
12. With the Tech 2 scan tool, clear any DTCs.

30 MINUTE LEARN PROCEDURE
1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON; the vehicle will not start.
3. Observe the SECURITY telltale; after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.
6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.

IMPORTANT: The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

7. With a scan tool, clear any DTCs, if needed. History DTCs will self clear after 100 ignition cycles.

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Let me know if this helps

Joe