car won't start-help with alarm/immobiliser issues

[mackenzie50]

Hi guys- the good weather has arrived and my late model ABY languishes in my local garage...I've placed it there as when I recently went to start it in its lockup it wouldn't start-and I ran the battery down before I could trouble shoot properly. I should say in the short period of ownership I had taken it out on very short runs but maybe only 4 occasions in 2 mths. I bought the car from a forum member who supplied no alarm fob and stated it did not need one- the key supplied opened the driver's door lock, and on placing in ignition simply started the car- no probs, or so it initially seemed.
Now upon charging the battery and re-installing it, the alarm has kicked off bigtime and immobiliser seems to be preventing engine from cranking over...and you lot won't be surprised to hear that the key in the ignition doesn't cancel the alarm...
I wasn't on the ball with this purchase- I bought too quickly and missed some issues, but heyho- we're all wiser after the event (I was a tad distracted as my wife was 8 mths pregnant with our new baby boy..yup ,she let me buy another S2-she's a good'un!)
But now I can't even drive the flamin' car while I save up for eventual remedial repairs. It was in good driving form before the alarm/immobiliser trouble.
So, I take it the immobiliser is contained within the ECU, and my garage won't be able to de-immobilise it-as it's a rare specialist task?
Am I best to source another 2nd hand ECU? Any help appreciated...my garage have built an ABY engine UR rally car in the past but may not have all the wiring diagroams/info they need...

cheers in advance, Col.

[mackenzie50]

PS -it seems to be a factory alarm/immob. installation but not 100% sure.

[K Simmonds]

Sounds like you have an after-market alarm fitted, sometimes a quick way to get around that with no key fob is to disconnect the battery, turn the ignition to the on position with the key, reconnect the battery then try starting it.

If that fails the best bet is to remove every trace of the after market system and join the wires cannibalised in the install back together, it's much easier than it sounds, can be done in a couple of hours.

You shouldn't have to touch the ECU, the car may have a factory imobilser but the wiring for that will be distinct from the after market stuff.

[mackenzie50]

Thanks for that positive post, Kit - I'll speak to my garage soon-they only took the car in a coupla days ago...

[GazzaG60]

is the alarm on the horn or seperate box.

my aby used to set off the factory alram (horn) after a battery charge, i had to lock all doors and then unlock from passenger side to disengage in this instance. i also had an after market (toad) never an issue with that.

if tis the horn one make surew boot, bonnet and all doors are shut. lock and unlock then inlock from passenger side and then open drivers door iirc. sometimes the indicators would flash for 5 mins or so. didn't do it every time i took battery off. maybe 1/5

hth

[mackenzie50]

is the alarm on the horn or seperate box.

my aby used to set off the factory alram (horn) after a battery charge, i had to lock all doors and then unlock from passenger side to disengage in this instance. i also had an after market (toad) never an issue with that.

if tis the horn one make surew boot, bonnet and all doors are shut. lock and unlock then inlock from passenger side and then open drivers door iirc. sometimes the indicators would flash for 5 mins or so. didn't do it every time i took battery off. maybe 1/5

hth

Cheers for that info! Will follow that sequence up- every tip/ suggestion gratefully received

[andy10v]

Did you grab a picture of the alarm box under the bonnet?

[johne]

If the car is factory standard, then the alarm is activated/deactivated by opening the driver's door with the key and the immobiliser works automatically with the key in the ignition - as long as it's an original key with the immobiliser chip in it and not one you've had cut.

If some aftermarket alarm has been fitted, then all bets are off but as you managed fine with just the key from the previous owner it sounds as though you have a factory standard car.

The unit that reads the chip in the key is behind the instrument cluster but as you say the immobiliser function itself is in the Motronic ECU and not easy to bypass.

The factory immobilser doesn't stop the engine from turning on the starter motor, just stops the engine so if you can't turn the engine over you either have an aftermarket alarm/immobiliser or some other problem like a faulty ignition switch.

John

[mike74]

If its the factory alarm/immobiliser that's wonky it should allow the engine to crank and run for a second or two. There should also be a yellow dash warning light with a car and a key on it flashing.

[K Simmonds]

We could do with a photo of the unit under the bonnet and also one of the rat's nest that is hidden by the drivers side under steering wheel shelf, it should be held on by a few 8 mm head screws.

Most of these car's have had a member of Mencap let loose under the dash with Scotch lock's, insulation tape and if your lucky solder & heat shrink. Anything non Audi will be obvious. Do you have any LED's fitted to switch blanks etc?

I have a 'system' to deal with on my recently acquired RS2, that has the factory type alarm described above but there's other stuff under there as well.

The factory system is normally reliable.

Can you pull the fault codes?

[andy10v]

Does the engine turn over but not start?

Or does nothing happen when you try and start it?

[mackenzie50]

Does the engine turn over but not start?

Or does nothing happen when you try and start it?

Nothing happens, Andy, when one tries to start the car- but.. immediately after I re-installed the battery and just before the alarm kicked in...it did crank over for a short while, but not start.
It was the turning over but not starting issue that initially prompted the removal of battery to charge it btw.

[andy10v]

Does anybody know if the factory alarm had an alarm box under the bonnet with a round key?

The Alarm box in the engine bay had a key hole like this in the side of it

[andy10v]

And the alarm siren is going?

[mackenzie50]

We could do with a photo of the unit under the bonnet and also one of the rat's nest that is hidden by the drivers side under steering wheel shelf, it should be held on by a few 8 mm head screws.
Do you have any LED's fitted to switch blanks etc?
Can you pull the fault codes?

My 'bad' in not getting a photo of underneath the bonnet, or dash, Kit...not giving you guys all the info/clues ,when i'm asking for help! And it's in a garage some 20mls away, but I'm hoping to get over there on Thurs to see if any progress made at their end, and if not will pursue the photo opportunity. No LEDs btw.
Did the factory alarms ever have the rectangular alarm pods mounted in the interior pillars, both sides of the windscreen?