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Alfa Romeo 145 - 146 Forum _ ECU Diagnostics _ Immobilizer Problems

Posted by: AnthonyT16 11th February 2015 18:59

this started like a month ago.... to close the car i would need to press the key button like 20/20 times in order to get the doors locked and the alarm active, today seems like it's definetely dead.

i spent 10 minutes by pressing the key button but the car didn't close at all, and this is a problem since i don't have the locks on both doors, i refuse to close the car by entering from the trunk like a thief.... can you imagine the scene?!

i checked out the fuses and nothing seems to be wrong there, checked the 2 CR2026 batteries and i got 6.2v on both and 3.2v on each batteries ... but the car wound close anymore! so i took out the transponder but i didn't saw anything there... what i saw was a button aside the green led

what is that? i pressed, it started flashing, tried again to close the car, no way.

What else must i check?!

Posted by: alfizta 11th February 2015 20:12

check central lock unit on fusebox. usually a big yellow relay.
recently found out mine was faulty. sometimes doors locked, sometimes not. problem gone after replacing for a 2nd hand one.
I think there is no way to tell if it is faulty unless you try another.

Posted by: black 146 12th February 2015 01:29

you have a relay on the main fuse board on the left 3rd up from the bottom and a 20Amp fuse 5th one down on the the left

Posted by: AnthonyT16 15th February 2015 07:36


found the issue, it's from the key itself.

Posted by: GialloEvo94 15th February 2015 10:17

QUOTE(AnthonyT16 @ 15th February 2015 07:36) *
found the issue, it's from the key itself.

You'll most likely find that the microswitch on the circuit board in the key is either knackered or is gunked up with some black sticky residue. To clean off any gunk, use isopropyl alcohol and an old (small) toothbrush. Make sure you also clean any gunk from the inside of the rubber button as well. If the microswitch is knackered then just get someone to replace it for you who is good with a soldering iron and surface mount components. The microswitch is a If you only need a single new microswitch and don't mind paying over the odds for a one-off purchase then you can get them on eBay

Posted by: AnthonyT16 19th February 2015 23:49

the problem is not the microswitch, is the little metallic part from the microswitch board that doen't make a proper contact with the other surface, causing this some kind of bad communication beetween the chip on the key and the car receiver, i'll put some pics of what i'm talking about.

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