Engine Immobilizer Malfunction?

Completely out of the blue, my truck wouldn't start this morning — ignition cranks just fine but the engine won't start. I've ruled out the battery.

I have a theory that it's the anti-theft immobilizer that's been activated somehow. I kind of fumbled with unlocking it this morning as I was rushing to get going... maybe pressed the panic button as I mashed all the buttons on the fob.

I've noticed that the immobilizer security light continues to flash even after I've inserted the key and attempted to start it. My understanding is that the indicator light should turn off after the paired key is inserted into the ignition...

I've checked fuses, disconnected the battery — tried some weird reset sequences I found elsewhere online. Nothing. Truck still just cranks, as if it's going to start any second.

Any ideas? Thinking of attempting to reprogram the ECU with a paper clip (YouTube) but not feeling very good about that idea.

 

Stupid question but have you tried other keys? This is a manual transmission right.

If its flashing, there's no reset that will fix it, you need a techstream at a dealer.

I would 100% suggest disconnecting the battery and letting it sit for 30 mins, it won't hurt.

 

I've tried my other key and disconnected the battery for 30 minutes at least (neg terminal). Nothing.

 

Are you sure it’s not flooded? Mine would randomly do that on the factory tune somewhat often.

Peg the throttle to the floor while it cranks

 

Huh. I did feather the throttle a bit but I haven't tried that — I'll give it a go in the morning.

 

I had same issue out of the blue with my altima. Turned over just fine even though it was push button start. Tried several times and figured battery was weak so trickle charged overnight and next day while at work. Came home still wouldn’t start. Figured I’d take it in since under warranty. Decided to try again next day and gave it a little throttle and nothing but it did finally act like it was firing a bit. So I floored it and it started. Tons of smoke poured out the back when it started but haven’t had an issue since. Figured it blew out some carbon build up and it’s been fine for 15-20k miles no issues.

Not saying this will fix your truck but from my experience worth a try before heading in for repair.

 

Yeah no luck with the throttle either... can't get it in at the dealer til Monday.

Still would like to avoid having to take it in at all. Any other ideas, sensors, fuses, _____ I can pull, unplug, check, etc?

Considering trying this, as that seems pretty identical to what's happening w me. But I'm very hesitant with all the computers onboard. There are similar videos for newer model Toyotas/Lexus, no evidence this will work on a 3rd Gen Tacoma at this point... any thoughts or experience with this technique?

 

Keep us posted if you try it.

G.

 

Did this to my truck last week, worked like a charm. Granted I did a full ecu replacement, so I had to do this. Most likely will be exactly what the dealer does.

 

Ok so I did try the paperclip thing — and the lights in the cluster responded as suggested, so I think the procedure was done correctly. But it didn't end up making a difference. So maybe I'm wrong about the immobilizer? Or maybe this fix doesn't affect the immobilizer on the 3rd gen? That car+lock icon is still blinking in the console, and continues to blink in both accessory and on ignition positions, and even when i'm cranking the engine over.

Can others confirm that this behavior with the anti-theft light is out of the ordinary? Or do yours continue to flash until after the truck starts?

 

How long did you let it sit for? It’s gotta sit with the pins crossed for 20-30 minutes and ignition switches to on. Then turn the truck off. Then try starting.

I’d assume if this doesn’t work it’s gonna have to goto the dealer.

 

Yeah tried it twice actually... waited 30 minutes the first time. Waited maybe 40 the second, and gave it a jump for the second attempt on the start just to be double sure.

 

My brother had this problem with his Tacoma with 60,000 miles.
Truck would randomly not start after being driven.
A Gas station stop would end up with the truck not starting.

Ended having it towed to the dealership and they couldn’t find the problem because it was random.

After multiple no starts the Dealership ended replacing every part of the immobilizer, from keys to antenna, power supply, etc.
Still didn’t fix it.
Toyota sent in a hot shot tech to the dealership for this particular ticket.

Replaced the ECU and reprogram it too.

3500 later toyota could not find the problem. They said maybe it was part of the wiring harness and wanted 1000 more to keep going forward.
Was out of warranty

He traded off the truck with the problem, hopefully you don’t go down that road.

The electronic can be a nightmare on these trucks if something goes south

 

If anyone happens to notice — I'd be interested to know at what point your anti-theft light in the console turns off. Does is turn off when you insert your key? Or after you're in accessory or on? or cranking, of after?

 

Have you done any mods to your truck?
There was someone on here a while back that put LED lights in his truck and it malfunctioned the break pedal start sensor thing.

 

It turns off with key inserted. Doesn't need to be turned.

 

No electrical mods—just wheels and tires so far.

 

Thanks man — this is helpful. I feel like maybe I am correct about the problem but I just can't fix it who knows.

 

Was able to pull this immobiliser code with the BlueDriver OBDII transmitter I just picked up! No idea what to do with this info but pretty cool to get this kind of data.

 

So you're literally stuck not being able to drive it? Dang, that sucks and sorry this had to happen. Have you gotten this resolved yet? I'm curious on the outcome...