my car security light flashes?

2008 SATURN ASTRA
110,000 MILES • 1.8L • 4 CYL • 2WD • MANUAL
Avatar
MARCELD
  • MEMBER
  • 1 POST
my car security light flashes and i can not start my car. when i unplug the neg from the battery, it will start. but when i leave the car, and then try to restart it, the security light flashes once again and it won't start.

do i need a new bcm?
Apr 19, 2026 at 4:34 AM
Avatar
STRAILER
  • ✓Experienced Mechanic
  • 55,549 POSTS
This means the security system gets enabled, this is why the security light flashes. Does the remote work? Also, do you use the key to unlock the drivers door, both of these actions will disarm the alarm. Also, we should run a CAN scan to see if any codes are present. I would not replace the BCM right now, though it might be the problem but lets do some testing first.

CAN SCAN - https://youtu.be/u-4syLc-ifQ

Please go over this guide and get back to us.
Apr 20, 2026 at 2:18 AM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle