Technical ECM replacement

[FLTH20]

My son has a 2012 Abarth 500. He has had the ABS, ESP and Hill Hold lights coming on on the dashboard for over a year. His mechanic has checked the diagnostic codes and it shows the ABS switch and has replaced the ABS switch (twice) to no avail. He has also changed the whole ABS module and synced it with the ECM, also to no avail. Finally, he has continuity checked all the wires to/from the ABS switch and module and, again, to no avail. His next recommendation is to change the ECM but he says you have to get the physical key that goes with the ECM. I've seen lots of ECMs on eBay but no mention of the physical key.

My question: Can anyone tell me exactly what needs to be done to change the ECM and all the parts you need?

Thanks very much for any help anyone can give me.

 

[bugsymike]

My son has a 2012 Abarth 500. He has had the ABS, ESP and Hill Hold lights coming on on the dashboard for over a year. His mechanic has checked the diagnostic codes and it shows the ABS switch and has replaced the ABS switch (twice) to no avail. He has also changed the whole ABS module and synced it with the ECM, also to no avail. Finally, he has continuity checked all the wires to/from the ABS switch and module and, again, to no avail. His next recommendation is to change the ECM but he says you have to get the physical key that goes with the ECM. I've seen lots of ECMs on eBay but no mention of the physical key.

My question: Can anyone tell me exactly what needs to be done to change the ECM and all the parts you need?

Thanks very much for any help anyone can give me.

What are the actual codes?
Many on Fiat Forum use the full version of MultiEcuScan with the correct leads and it will give specific Fiat data, so unless your son's mechanic has the latest Snap On diagnostics or similar he may not have all the information, which may explain why several parts have been replaced without a solution.
I would be very wary about expecting a replacement ECU to fix anything.
Certainly don't just buy a s/h ECU to be an answer.
If it did prove to be an anti lock Braking issue a good diagnostic will pinpoint exactly which wheel sensor or reluctor is at fault if that is the case.

 

[Mike1alike]

Sounds a lot like the problem is caused by bad voltage. Bad battery/alternator or even more so damaged ground cable. Should definitely have that tested before doing anything else.
In regards to ECM, it does read the chip code from the key everytime you start the car and checs if it matches with the one it has stored. If you go to the road of getting the key along with the new ECM I think that doesn't help you at all because there is another bit stored in the fuse box or so, so you'll need to get that one too from the car ECM is and replace it as well.
The easiest way, if you really need a new ECM is to have the IMMO data on it deleted. "Virginised ECM" they call it, some people selling ECMs are doing the wiping too so if you ever need one, you should ask them if they did, to know what you are buying. And that ECU once installed, the first time you turn the ignition on it reads the data on the key and stores it, that's its new IMMO code, the car will start only with your key.

 

[FLTH20]

What are the actual codes?
Many on Fiat Forum use the full version of MultiEcuScan with the correct leads and it will give specific Fiat data, so unless your son's mechanic has the latest Snap On diagnostics or similar he may not have all the information, which may explain why several parts have been replaced without a solution.
I would be very wary about expecting a replacement ECU to fix anything.
Certainly don't just buy a s/h ECU to be an answer.
If it did prove to be an anti lock Braking issue a good diagnostic will pinpoint exactly which wheel sensor or reluctor is at fault if that is the case.

Thanks for the prompt reply. I don't know the actual codes but I will definitely pass this along to my son.

 

[FLTH20]

Sounds a lot like the problem is caused by bad voltage. Bad battery/alternator or even more so damaged ground cable. Should definitely have that tested before doing anything else.
In regards to ECM, it does read the chip code from the key everytime you start the car and checs if it matches with the one it has stored. If you go to the road of getting the key along with the new ECM I think that doesn't help you at all because there is another bit stored in the fuse box or so, so you'll need to get that one too from the car ECM is and replace it as well.
The easiest way, if you really need a new ECM is to have the IMMO data on it deleted. "Virginised ECM" they call it, some people selling ECMs are doing the wiping too so if you ever need one, you should ask them if they did, to know what you are buying. And that ECU once installed, the first time you turn the ignition on it reads the data on the key and stores it, that's its new IMMO code, the car will start only with your key.

Thanks for this info. I will pass it along to my son.