TheRedPirate

My friend had a fuel cut defenser on his s4 turbo 2 but then he bought an ecu that had one built in and so he gave me the fcd. I have an s5 turbo 2 but when i put the fcd in i got a check engine light. I checked what code it was and it was the senor that the fcd was connected to. When I unhooked the fcd the light went away.

I was wondering if s4 and s5 t2's require different fcd's, or if the check engine light was normal after connecting an fcd, or if the fcd I have is just broken.

dawicka2

According to racingbeat.com, they are different.

Sell your s4 fcd and buy an s5 one.

John ny

The Griffin

The S4 has a 5 volt line going to the map sensor ,whereas the S5 just has a 12 volt line there I believe. If the FCD is a clamping type (instead of just a cheap resister in series type) then it needs a 5volt input.If you didn't burn something up already in the FCD you can install it just before the ecu by taping into the proper map sensor line and a 5 volt "vref" line there(tps vref line). The diff. in the S5 FCD is that it has a 12volt to 5 volt regulator built into the circuit.

TheRedPirate

ok thank you both, you've been helpful