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Discussion Starter #1
Chaps,

After several searches on the subject, I've failed to find a definitive answer to how to make a new (new to vehicle) Engine Control Unit work with the existing keys/immobiliser...

So far, I've found 3 different answers:-

1. You need the keys and immobiliser from the "new" ECU's donor vehicle.

2. Someone with a TECH2 set will have to recode the ECU.

3. There's a cunning way to make the immobiliser recognise the "new" ECU which features leaving the battery disconnected and/or re-connecting the immobiliser after the "new" ECU is connected and powered up..

Any guidance would be a great help!
 

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Well to start the keys are not important it is the transponder inside the key that signals the ecu to turn the immob of via the receiver that is around the ignition barrel if you are/have replaced the ecu you need the transponder(out of the keys the ecu came from you don't need the keys) and the receiver as there a matched set,but i have heard of people being able to use there exsisting receiver with a new transponder and ecu.
If you didn't and cant get the transponder to go with the new ecu you can get your existing transponder programmed to the new ecu with tech2.
 

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Gas Powered
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Tech2 will do it (I did it to the Estate)

Other option is to get the tranny reader, chip and ECU from the same car.
 
R

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all i know for definate is a spare key is about 80 quid. And i saw a post about someone turning ignition on with both key buttons pressed to enter programing mode (dont take my word 4 anything what i mean is i dunno what order or anything) and i think its to set your immobiliser to be honest but i really dont no. not sure if it shows on the tid or anything like that as iv got a fragmented one at the moment, hmm i`m not much help am i
 

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Discussion Starter #6
As I suspected, the car didn't like the new ECU... If the supplier of the new ECU doesn't have the transponder reader and the key chip to match, I'll see who's got a TECH2 kit in the area or send the old ECU off for repair.

At the moment I'e only spent £45, so I'm way short of the £300 I was quoted for a reconditioned and tested ECU reprogrammed to match the existing key and reader...

Thanks for the help!
 

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The "trick" of pressing the fob buttons whilst ignition is on ONLY works for existing fobs that have already been married to the ECU. Buying another fob and trying it won't work.
 

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Discussion Starter #8
Quick update.

Breaker's didn't have the key chip and transponder to go with the "new" ECU, so I sent the old one off to get it checked out and the nice chaps at Autotek couldn't find anything wrong with it and advised that it was worth swapping out the crank sensor so I have one of them in the post too.
 

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Discussion Starter #9
On removing the old crankshaft sensor, I found the cable had been crushed/torn/chaffed by the timing belt and the insulation on all three wires was stripped back allowing them to short out against each other and the engine whenever the cable moved around.

Moral of the story: When the flash code say "Faulty Crank Sensor"; take 5 minutes to visually inspect the cable and connections. You might save yourself £'s!

Of great assistance were:-

Autotek (http://www.electroniccarparts.com/) for checking out and returning my ECU in 24hrs as well as giving me loads of fault finding advice.

Auto Vaux (http://www.autovaux.co.uk/index.asp) for not only sending me a fax picture so I could tell if I had the X18XE or X18XE1 engine, but for getting me a new cranks sensor by 9am on a Saturday morning when I ordered it at 3:30 pm Friday afternoon!
 
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