Author Topic: Immobiliser control unit  (Read 1439 times)

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Offline Byork

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Immobiliser control unit
« on: October 13, 2017, 14:52:55 PM »
Hi all, on the back of my last post about dash lights not turning off , by using the paper clip test one fault is immobiliser control unit which will explain why the car won't start , does any know how to sort this , car is fitted with a Clifford alrm/immobiliser, thanks in advance

Offline agw9262

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Re: Immobiliser control unit
« Reply #1 on: October 14, 2017, 07:56:45 AM »
Hi all, on the back of my last post about dash lights not turning off , by using the paper clip test one fault is immobiliser control unit which will explain why the car won't start , does any know how to sort this , car is fitted with a Clifford alrm/immobiliser, thanks in advance

If you’re getting a fault code from the immobiliser, it’s not coming from the Clifford unit but instead the standard factory fit immobiliser. That consists of 3 major parts - a chip in the key; a collar around the ignition barrel that reads the chip and “unlocks” the ECU and then an ECU that expects the “unlock” code from the collar.

Do you have a spare key with a chip in that you can try for starters to rule out the chip?

Offline Byork

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Re: Immobiliser control unit
« Reply #2 on: October 14, 2017, 09:35:49 AM »
I only have one key which has never had a battery in it, not sure if that would have any impact on the chip? I would of thought when the Clifford was fitted the original alarm system would be disconnected? Will I need to replace the barrel?

Offline tristandimond

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Re: Immobiliser control unit
« Reply #3 on: October 14, 2017, 09:44:21 AM »
The battery does not affect the chip. The aftermarket alarms are usually in addition to the factory spec and so they would probably have left the original security on.
The chip doesn't have a battery it is just detected by the reluctor ring around the ignition barrel.
Unfortunately replacing the barrel wont help as the immobilizer unit will still be coded to the chip (as long as your key still turns in the barrel).
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Offline agw9262

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Re: Immobiliser control unit
« Reply #4 on: October 14, 2017, 09:48:25 AM »
The chip is present in both the battery key and spare key - it’s a small black wedge - as Tristan said it doesn’t use power so the battery is irrelevant (used for the light in the key...). If neither key will start it and you’re getting immobiliser codes you’ll need to fault find further or get a complete set of chips, collar and ECU. They’re paired. As for the Clifford - even when they fit that they have no way to disable the original. Though I’d wonder if/how it might be part of the problem.

Offline Byork

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Re: Immobiliser control unit
« Reply #5 on: October 14, 2017, 09:50:55 AM »
So what would be my next move on this ? Have read my last thread about dash lights staying on? This has all started with that

Offline tristandimond

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Re: Immobiliser control unit
« Reply #6 on: October 14, 2017, 09:58:46 AM »
Ive read your other post, and have no idea what could be causing the dash lights other than a crossed wire.
You said it was affected by the brake being pressed, so have you checked if this is crushing any wires at all?
Thats the only reason i could think of the brake pedal affecting it.  :-\
If the immobilizer unit has failed then rather than trying to find a matched key chip, immobilizer unit & barrel sensor it may be easier to get the unit bypassed as you will still have the clifford unit.
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Offline Byork

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Re: Immobiliser control unit
« Reply #7 on: October 14, 2017, 11:14:00 AM »
Is there wires near or around the brake pedal?

Offline agw9262

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Re: Immobiliser control unit
« Reply #8 on: October 14, 2017, 11:27:54 AM »
Not normally but the aftermarket alarm fitter might have run some near there.