Not starting, possible security issue?

Tiny
DJPHOOKA
  • MEMBER
  • 2007 LEXUS IS 250
  • 1.6L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 181,000 MILES
The alternator was replaced a few months ago, I replaced / warrantied the battery yesterday brand new stickered 1/25. It wouldn't start initially and also the alarm didn't go off when the negative was reattached but there is full power.

After troubleshooting and racking my fkn brain I used the FOB next to the ignition to get it started once, that tripped the alarm system which I disarmed. It was idling high, I let it run for 5-6 min and shut it off, but it won't even do anything unless the battery is disconnected/reconnected and now won't start with the FOB next to it. The A/C works, radio blasts, windows roll, and the lights are bright. But when I click the ignition, it clicks off.
Thursday, January 30th, 2025 AT 2:42 PM

4 Replies

Tiny
DJPHOOKA
  • MEMBER
  • 4 POSTS
After brand new swap.
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Thursday, January 30th, 2025 AT 2:52 PM
Tiny
DJPHOOKA
  • MEMBER
  • 4 POSTS
Ooops, duplicate. This was the initial problem before warrantying the battery.
Thanks for any advice.
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Thursday, January 30th, 2025 AT 2:55 PM
Tiny
DJPHOOKA
  • MEMBER
  • 4 POSTS
It was a security issue after installing the new battery. You have to keep the fob close while the car idles for about 15 minutes. Do this with the doors closed and hood latched. Tried the alarm and it went off and then was able to disarm and start the car.
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Friday, January 31st, 2025 AT 1:31 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,525 POSTS
I don't think the security system will make the dash go dark as it did, you say the problem is fixed? Thanks for the video, it helps. Can you tell me if the dome lights go out as well? If so, I would say the power source control ECU is going out. We can tell for sure if you do a CAN scan which should show the codes of the source of the problem. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

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

Here is the location of the power source control ECU so you can check the wiring connectors for corrosion and if okay replace the unit. They call it a gateway ECU. Check out the images (below). Please let us know what happens.
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Saturday, February 1st, 2025 AT 11:07 AM

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