# what does a blinking key light on the dash board mean?



## samiibn (Oct 15, 2003)

*what does a blinking light on the dash board mean?*

i just replaced my ecu...when i turned the car on to test it...the car turns on...then right back off, and a blinking key icon goes off on the dash, as well as a EPC light....whats wrong? the ecu is the same code as mine...why is it not working?


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## Durbo20vT (Apr 30, 2006)

immobilizer is preventing the car from starting. the ecu's immo needs to be matched to the car, or immo clone/defeat on the ecu in order to run with your cAr


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## adg44 (Aug 2, 2000)

*Re: what does a blinking light on the dash board mean? (samiibn)*

You need to code the immobilizer on your new ECU to your key. 
This is easy to do with the 2001 and earlier cars compared to the later ones with the newer immobilizers (which require a dealer code).


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## samiibn (Oct 15, 2003)

*Re: what does a blinking light on the dash board mean? ([email protected])*


_Quote, originally posted by *[email protected]* »_You need to code the immobilizer on your new ECU to your key. 
This is easy to do with the 2001 and earlier cars compared to the later ones with the newer immobilizers (which require a dealer code).

how whould i do this:?


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## samiibn (Oct 15, 2003)

*Re: what does a blinking light on the dash board mean? (samiibn)*

what are the step i need to take to get the ecu mated to the key?


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## Durbo20vT (Apr 30, 2006)

you wont be able to do it. either the dealer can mate it for you OR a revo/giac/apr/uni dealer would be able to clone/defeat the immo on the ecu


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## Boostin20v (Mar 22, 2000)

*Re: (Durbo20vT)*

http://www.ross-tech.com/vag-com/cars/index.html
Read the Immobilizer info posted there for instructions.


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## samiibn (Oct 15, 2003)

*Re: (Boostin20v)*


_Quote, originally posted by *Boostin20v* »_http://www.ross-tech.com/vag-com/cars/index.html
Read the Immobilizer info posted there for instructions.

thanks guys...big help


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## snaggndragon (Oct 25, 2015)

*Just had this happen to me*

Okay, so I just replaced the plastic housing on my key fob because the old original was broken and falling apart. I ordered the new one from Ebay and replaced the old one. ALL of the innards and the battery are the EXACT same. Now In can't start or drive my car. WTF? I looked into the the link provided by "Boostin20v" but don't quite understand what I'm reading. I have an '03 Jetta GLI VR6 24v. Same problem as original post. Car starts, and then shuts right back off. Someone please help. I cannot afford to tow my car 30mi. to the dealership. Thanks.


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## snaggndragon (Oct 25, 2015)

*Update*



snaggndragon said:


> Okay, so I just replaced the plastic housing on my key fob because the old original was broken and falling apart. I ordered the new one from Ebay and replaced the old one. ALL of the innards and the battery are the EXACT same. Now In can't start or drive my car. WTF? I looked into the the link provided by "Boostin20v" but don't quite understand what I'm reading. I have an '03 Jetta GLI VR6 24v. Same problem as original post. Car starts, and then shuts right back off. Someone please help. I cannot afford to tow my car 30mi. to the dealership. Thanks.


*


Alright so after taking a deep breath and not being in a rush to get to work in a car that won't start, I sat down and did some thinking. I remembered I had a valet key and went and tried it on the car and it worked. I then thought some more and figured I would disassemble the new key fob and the old one to inspect them side by side. I found nothing different about the two with the exception of a small black "pill" looking thing buried in a crevasse in the old fob. I took that little thing out and put it into the new fob and put it all back together. Then the magic happened.  I went to the car and gave it a try and waddya know. IT WORKED!!! 

So thanks for the good vibes from the forum. I guess I just needed to join the group so I could start feeding off the wealth on knowledge here in the forums. :screwy::facepalm: *


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## Human Garbage (Jan 3, 2014)

That 'pill' is a Megamos ID48 RFID chip. And as you figured out, that is what is read by the car to authenticate the key... If you want more keys you can buy them on Ebay for $2/ea and pair them to your car with VCDS.


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