Immobiliser won't let me start the car

[Starbuck]

Filled my MR2 up at the petrol station last night and had problems getting the immobiliser to unlock the car.
After a few minutes it worked.
When i got home i changed the battery in the fob.
This morning i go out, use the fob and the alarm goes off!
After 30 seconds it stops and i can get into the car.
But the ignition is still immobilised.
Fob will lock and unlock the car, interior light comes on when car is unlocked.
Today i read on the internet that some fobs need to be paired up again with the main unit after changing the battery..... so this would seem to be the case here or it's a very spooky thing to have happened just after i changed it.
It's a Microscan immobiliser, i didn't fit it nor did the previous owner....so i'm unsure of the model.
But doesn't seem to be a top of the range model as it has no motion sensors etc fitted.
Seems to need a key to pair the two units again or to disable it..... but i don't have the key, nor does the previous owner.
Will try and ring Microscan tomorrow and see if there's another way to pair these things up.
If they can't help, i may have to remove the whole immobiliser.
It can only be immobilising the ignition as i can start the car by bump starting it.
But that's not practical.
I got this wiring diagram from there site:



Seems to be fairly easy if i've only got to reconnect the ignition wire where it's cut in the diagram.
But the big question is.... is it that straight forward?

[Tsia]

bu88er, had my hopes up that I could help there, after experiencing hell with the standard immobiliser for months on end. It's usually a bit more complicated than joining the 'cut' as I found out...

Good luck, though!

[Starbuck]

Thanks for taking a look anyway.

[Tsia]

I'm waiting for a friend to come online that was able to circumvent my own immobiliser to get my car working once again to show him your wiring diagram. As I know it's a public forum, I won't post the information here, but hopefully something that you can use via PM (as long as that's allowed? Mods tell me if not, don't want to go breaking rules )

[LimeyMk1]

As I know it's a public forum, I won't post the information here, but hopefully something that you can use via PM (as long as that's allowed? Mods tell me if not, don't want to go breaking rules )

A wise way to proceed and no probs from our end.

Best of luck getting it sorted Peter, alarms/immobilisers can be a PITA at times.

[Tsia]

PM sent! Cheers for clearing that up for me too, Limey.

[Starbuck]

As I know it's a public forum, I won't post the information here, but hopefully something that you can use via PM (as long as that's allowed? Mods tell me if not, don't want to go breaking rules

Can i just add here that i'm not looking for an illegal way to break into the immobiliser.
Just a way to either pair the 2 units again or attempt to take out the old immobiliser and fit a new one.

One possible solution that was given to me today, is to disconnect the battery from the car and then let the back up battery in the immobiliser run down. (could take a couple of days)
Once the back up battery has gone dead, all codes etc will be wiped out.
Then when the main battery is reconnected and the fob is used, the main unit should register this code and use that.
It seems to have worked for some people.

[Tsia]

Good luck with it either way! I understand how it is, I had real issues with mine a few months ago and most seemed hesitant to tell me how to bypass the Toyota immobiliser, understandably. Truth be told, you could figure it out with a brain cell and a pair of scissors.

[Fozzy]

If it is definately that model of alarm then it really is as simple as joining the cut wires back together on the back of the ignition switch. I fitted a couple of these alarms, they are pretty crude, much better ripping it out and fitting a Toad Ai606

[Starbuck]

Well waiting for the back up battery to die, didn't work.
Thought i'd take a look myself, so took out the dashboard panels to have a look.
OMG what a mess!
Looks like most of the connections were made in about 15 seconds.
Obviously the immobiliser dashboard light wiring wasn't quite long enough.... so the idiot decided it was good enough to just twist some more wire on:



Some of the other wiring isn't a lot better.
So i've decided to get an auto electrician to take out the immobiliser and check all the other wiring, before fitting another immobiliser.
And to think i've been driving around with this dodgy wiring for 3 months. ( since i bought the car)
Some things you just never think to check.

If it is definately that model of alarm then it really is as simple as joining the cut wires

I looked on the Microscan site and looked at all the parts they sell.... apart from the key fob nothing that this idiot used even looks remotely like the Microscan parts.
I'm beginning to think he's just used parts from anywhere and assembled them into an immobiliser.
Much better to have a proper system and have it fitted correctly.

[Starbuck]

All sorted now.
The auto electrian stripped out the immobiliser and checked all the wiring and replaced what he thought was dodgy.
Even sorted out my speaker wires which were loose.
So not just a safe car now.... a better sounding stereo. lol

Btw:
it was a Microscan Pro 400 that had been fitted..... but fitted very badly!

[stace110]

Glad you got it sorted bud ...I had a rover coupe and one day i left the foglights on and the imob cut in and i couldnt get if off ....ballache £400 later

[nickg07]

I've got a toad on mine and the second day i got the car somehow the door mechanism locked my drivers door open and it couldn't unlock to be able to shut the door. Not pleasant.