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Anonymous
Anonymous asked in Cars & TransportationCar MakesChevrolet · 2 weeks ago

2014 chevy sonic LT anti theft system activated, stuck on what to do next?

My father in law had his anti theft system set off, he stated it happened after driving to the dentist.

Let's start with the first step people try, key fob batteries, he had 2 keys, both didn't work to start the car, I checked and replaced batteries, problem persisted.

I disconnected negative battery for an hour, problem persisted. 

This is all I get through this process. First turn for key, everything normal, second turn, anti theft light and check engine light, trying to start, clicking, and only clicking.

I tried a ten second key in door trick I found on YouTube, nothing.

I used a ten minute with key in on position trick. IT WORKED, we were hyped. He told me to try remote start, I got locked out. Reset worked, I tried driving it, parked, locked out, reset no longer worked, and same problem persisted

Before I tried these steps he already bought a new immobilizer, so that is what I replaced, I was thorough, made sure everything was correct, and even double checked. Now the problem seems worse. In the on position every light goes out on the vehicle, first key position, only anti theft and battery light (battery is good, tested and tried jumping prior to test) are on, as well as the blue lcd is illuminated only showing the gear and miles.

I'm completely stumped, and we don't have the money to spend 1000s on a mechanic. Am I missing something simple here? Any suggestions? What (and how) should I test next?

Thanks for any help you can give.

Update:

Edit: no codes, run position only shows check engine light, obd reader reads no codes or past codes.

Update 2:

SOLVED: Although I got the battery tested, it had some corrosion so I tried a swap, the battery from my car worked, I believe a battery short caused the immobilizer to become faulty, a battery and immobilizer replacement solved the issue. For the person saying I threw money at this. The immobilizer cost $40, the $200 battery was after this question, and the problem is solved. In my opinion, the same cost a diagnostic can cost to fix the problem is not throwing money at this problem. 

Update 3:

For anyone else who ends up finding this post, don't listen to the guy saying to go straight to a mechanic, do your research, test things properly, set a dollar amount and if you surpass it, see a mechanic. I've learned everything I know on my own and through research, the sketchiest part of this process was the airbag removal necessary to get to the immobilizer, but I researched it, was careful, and saved my family a lot of money. 

Update 4:

The immobilizer on this vehicle does not need to be programed to the pcm :), the starter was engaging, the immobilizer is simply what reads your key chip, it does not have the memory of your key chip. Key words here: ON THIS CAR. do your research. 

Update 5:

Final update: the jump was prior to the immobilizer change, I believe this is why the car would not start, this was a simple fix, on a complex system, which is why I'll stick to my old vehicles 😂 Goodluck to all of you learn on your own mechanics, keep at it.

2 Answers

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  • Geo
    Lv 6
    2 weeks ago
    Favourite answer

    What a mess you have. The only thing I can think to do is start from scratch and reset everything to default settings. You would do that by doing a Capacitive Discharge. That is removing both Battery Terminals and hold them together for several minutes. Every memory will be erased and it will be the same as when the car was first built. If the security light is flashing or doesn't go off you'll need to the Key On for several minutes routine

  • thebax2006
    Lv 7
    2 weeks ago

    The immobilizer only stops the fuel injectors from working. it doesn't keep the starter from working. Do a voltage drop test on the battery negative ground cable. Clean the battery negative cable on both the ground to body and engine contacts and the inside portion of the battery clamps where they contact the battery posts. Remove any after market remote start systems. You're wasting the money you should have used to take the car to a master mechanic on throwing parts at it with your guesses. I'd put the original immobilizer back in the vehicle. I didn't see anything about you programming the new immobilizer to the PCM. You need a factory scan tool to do that. 

    Source(s): Mitsubishi Master Tech
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