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147 immobiliser failure

4K views 5 replies 5 participants last post by  Gino-93 
#1 ·
I have a problem with my alfa, i have done a complete engine transplant and have now went to start it with this fault coming up on dash. I had fixed the key (as mine was cracked) with a new shell with all the same internals of the original key so i assume it should be good as it started with the key before the engine transplant. Is the small tablet like bit in the key the transponder?its near the top of the key and is very tiny?, excuse my description. anyone any ideas?, could it have lost the code in the ecu from sitting with no battery?, i thought there is an internal battery in the ecu to store important codes etc, any ideas greatly recievede as i need going asap, thx guys
 
#2 ·
I am not sure now, but the transponder in the key looks like a small glass vial with piece of metal inside.
And there is no internal battery in ECU keeping the codes live. They are stored in ROM. But it is possible to lose the immobilizer/key connection, it happened to me last Christmas when the car was standing for 6 weeks and battery went flat. I had immobilizer error after and keys had to be re-coded to be recognized again.
But I don’t think that it would be caused by removed battery, I had car with no battery for a year and it didn’t happen, however low voltage of a connected dying battery made it loose immobilizer codes. So I think dead battery is worse that no battery at all.
 
#3 ·
If youve changed the engine have you a) used the same ECU as the old engine, b) checked the relays infront of the battery?
I you have access to alfadiag or the free fiatscan and an obd2 cable you can check to see if the immobilizer is picking up the key?

If you let people know roughly where you are there might be a helpful alfisti who could come and help you?
 
#5 ·
thx for the suggestions, I have not changed the ecu as i dont belive i need to unless mine is faulty, all earth straps are spot on as i made sure when installing the engine, I have acces to pretty advanched diagnostics but how would that show up under a general scan? it wont let me into immobiliser as mine is a magnet ecu not a bosch 1, i live in nutts corner northern ireland, cheers guys
 
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