Hi Guys,

I recently bought a Fiat Punto 1.2L and when pulling into a petrol station I noticed as I stopped, a shaking engine along with decreased power. I took it to my mechanic and he thought it was a simple Coil Pack problem and they were replaced. This didn't fix the problem.

I then today ventured to a local scrap yard to pick up a second hand ECU kit. This was the code box, ECU and ignition barrell. I delivered the parts to the mechanic and he began to work on the car. He rang me later telling me I am missing the key reader (immobilizer antenna). He says each antenna is key specific. I rang the scrap yard and they said that the one I have currently should work. At the current the engine attempts to start but with the Key Code symbol on the dash.

Do I need a key specific immobilizer antenna to read my new key?

Is there anyway to program the immobilizer antenna to be programmed to read my new key?

LenCabe said:

Hi Guys,

I recently bought a Fiat Punto 1.2L and when pulling into a petrol station I noticed as I stopped, a shaking engine along with decreased power. I took it to my mechanic and he thought it was a simple Coil Pack problem and they were replaced. This didn't fix the problem.

I then today ventured to a local scrap yard to pick up a second hand ECU kit. This was the code box, ECU and ignition barrell. I delivered the parts to the mechanic and he began to work on the car. He rang me later telling me I am missing the key reader (immobilizer antenna). He says each antenna is key specific. I rang the scrap yard and they said that the one I have currently should work. At the current the engine attempts to start but with the Key Code symbol on the dash.

Do I need a key specific immobilizer antenna to read my new key?

Is there anyway to program the immobilizer antenna to be programmed to read my new key?

Click to expand...

Antennas are not key specific. Did your mechanic read the OBDII codes to help him with his decision you needed a new ECU?

judderbar said:

Antennas are not key specific. Did your mechanic read the OBDII codes to help him with his decision you needed a new ECU?

Click to expand...

I don't know if he checked. I just got a text from him asking me to go get parts.

All I know is that I arrived down to him this evening and he said that I need to get the antenna from the car to which the ECU replacement parts came from.

Could it be possible to have a faulty key?

when you say code box do you mean the great big box behind the drop down fuse cover under the dash by your knee

LenCabe said:

I don't know if he checked. I just got a text from him asking me to go get parts.

All I know is that I arrived down to him this evening and he said that I need to get the antenna from the car to which the ECU replacement parts came from.

Could it be possible to have a faulty key?

Click to expand...

But how likely is that?



What you know is the key barrel is mechanically correct for the metal part of the key but:


1. you do not know if the transponder chip in the key is correct for the 'code box' which we are assuming is the internal fusebox with the attached body computer. and


2. You do not know if the 'code box' is correct for the engine ECU


Much depends upon how systematic and organised the scrappy was and whether or not your mechanic has plugged in the transponder antenna or mixed up the various boxes!


What you know about your mechanic so far is he lacks some basic knowledge about the items he is plugging together. It is not hard but he needs to be organised with the parts.



Phone the scrappy and find out how confidant he is that he gave you correct parts. Were the parts numbered/marked so they can be 100% identified on your car? Who now has the original parts that were previously on your car?

s and b said:

when you say code box do you mean the great big box behind the drop down fuse cover under the dash by your knee

Click to expand...

Yes the box by my knee.

judderbar said:

But how likely is that?



What you know is the key barrel is mechanically correct for the metal part of the key but:


1. you do not know if the transponder chip in the key is correct for the 'code box' which we are assuming is the internal fusebox with the attached body computer. and


2. You do not know if the 'code box' is correct for the engine ECU


Much depends upon how systematic and organised the scrappy was and whether or not your mechanic has plugged in the transponder antenna or mixed up the various boxes!


What you know about your mechanic so far is he lacks some basic knowledge about the items he is plugging together. It is not hard but he needs to be organised with the parts.



Phone the scrappy and find out how confidant he is that he gave you correct parts. Were the parts numbered/marked so they can be 100% identified on your car? Who now has the original parts that were previously on your car?

Click to expand...

The parts received from the scrappy are all marked with labels so we know what is what. The mechanic has my parts just sitting on the passenger seat with the scrap yards parts in my car.

Off the phone from the scrappy he said he is going to try and find another ECU in his store.