the immobilizer light was on (green key flashing) and will not start?

2007 HONDA CIVIC

145,000 MILES • 1.8L • 4 CYL • 2WD • AUTOMATIC

TREVOR FRIDENMAKER

MEMBER
1 POST

First, I got off work and went to my friend's house. Before I left, I popped the hood to check my coolant level. After leaving there my car wouldn’t start and the immobilizer light was on (green key flashing) but after I tried a few more times and locked the doors from the button on the inside it started, and I drove home. I made it home fine but now it’s doing the same thing again where the green key is flashing, and it won’t start. I don’t know if I knocked something loose when checking coolant or what. Also, my key fob lights up but doesn’t do anything when I press any of the buttons.

Oct 2, 2023 at 1:33 AM

STRAILER

✓ASE Certified Mechanic
54,832 POSTS

I have seen both the immobilizer key sensor go out or the MICU, you should do a CAN scan to see if any codes are stored.
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 how to check out the immobilizer key sensor which is probably the issue and in case code comes up for it and I have included the alarm wiring diagrams so you can see how the system works. Check out the images (below). Please let us know how it goes.

Images (Click to enlarge)

Professional Diagram for 2CarPros Members
Click here to log in and view diagram.

Oct 2, 2023 at 11:41 AM