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Weird alarm on 09 sierra slt

1523 Views 3 Replies 3 Participants Last post by  LAURASDAD
Is this normal? When unlocking the truck using the key, not the keyfob, the alarm goes off. It doesn't do it all of the time, but I haven't been able to isolate when it does it. I think it depends on if the truck is locked from the inside or maybe if it is locked with the door in the open position. Something like that but I am not sure.

But unlocking using the key does definitely set the alarm off. Any thoughts?


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If you use the key it is programmed to go off since there isnt anything telling the alarm to turn off. just be sure if you arm the alarm to use the key fob.
Your vehicle may have a content theft-deterrent alarm system.

To arm the theft-deterrent system:
1. Open the door.
2. Lock the door with the Remote Keyless Entry (RKE) transmitter. The security light should come on and flash. If the delayed locking feature is active, the alarm will not be activated until all doors are closed and the security light goes off.
3. Close all doors. The security light will stop flashing and go off after approximately 30 seconds. The content theft deterrent alarm is not armed until the security light goes off. If a locked door is opened without using the RKE transmitter, a ten second pre-alarm will occur. The horn will chirp and the lights will flash. If the key is not placed in the ignition and turned to START or the door is not unlocked by pressing the unlock button on the RKE transmitter during the ten second pre-alarm, the alarm will go off. Your vehicle’s headlamps will flash and the horn will sound for about two minutes, then they will turn off to save the battery power. This can also be found starting on page 2-18 of your owner’s manual. If you have further questions, please feel free to contact me. Thank you.

Tricia, GM Customer Service.
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wow, thanks for the reply. That absolutely anwers my question. I appreciate your help.

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