Originally Posted by Service Enginee
can't you add a new key to an immobilser ecu so why not add his existing key to a replacement ecu?
ok,some of the magic of immo coding explained
All new engine ecu's are virgin(no code),they pick up the code from the code box in the car the first time they are connected to that car.
Code 2 ,key chips are only programmed once and cannot be read.
Blank code boxes are programmed with the examiner with the code thats on the key chip ,if the car owner has the original code card with the number on.
Lets say now that we have a car that was working fine but the code box has a tantrum and goes faulty,we can then tap the code in the ecu through the gas pedal if we have that code card and the car will start.If however lets say we fit a new ecu that as i said is virgin and has no code in it at all onto that car with the faulty code box,guess what......it wont start.
It is possible if we have a faulty code box and no code card to read that code from the engine ecu and then with the examiner to write a new code box,Big problem though is that only very few of us can do things like that with engine ecus and have the skills and equipment to do it,and also it isnt cost effective for the customer with an old car.
One way of course round this is to deimmo an ecu which is what i do for the race cars,and then that ecu will start any car with or without code box,but we dont do that for road cars for obvious reasons.
This is a complex subject to explain,but i hope i have managed to give you a rough idea.