No communication to ecu

Romas

Member
Hey,after replacing engine wiring loom on 1.6 fsi,cant Start the car got no engine light on dashbord,there is no communication to ecu,did check on fuses and relays and ground wires all looks good what could I do next?,thanks
 
First thing id check is the new loom has the same part number on the tag as your original loom , id also check the wiring blocks between new and old looms for wiring ie, colour of wires to pin locations on each of the coloured block conectors , having had many days of chaos rewiring an A2 i know there can be several looms for the same model dependent on what year it was made and possibly your new loom is wired differently to your ecu, next if there identical looms and same part number id be checking the relays as sure one feeds power to the ecu when the ignition is turned on and then the two red power leads in the underfloor compartment where the front loom conects to the main loom , check those large fuses are clean on there fingers and where they plug into, theres also a fuse next to the positive terminal on the battery , unsure if this could affect anything but easily missed and worth a look see , theres also a main earth from the battery under the rear carpet bolted against the inner sill , just behind and below where the end of the passengers seat belt bottom bolt bolts to the inner sill on the outside of the carpet for a rough location .. I also check the main power lines red cables on the starter motor are all clean
 
Thanks for your replay,I only did visual on wiring loom that only match the sockets didnt look for color match on wires,wires on starter motor should be fine because it does run but fuel pump doest prime probably because of non working ecu,do you know where could I get diagram for ecu to check if it gets powered?
 
no idea about wiring diagram someone may be able to help with that but imagine it would be difficult with full details of your A2 as to so many varations, as you say its just iyour fuel pump not working, id be checking the relays in the underfloor compartment as one is the fuel pump relay i think.. but as you not 100 % sure if its the correct loom id be checking the part numbers on the 2 looms first before you go any further aswell as the wiring to the relay plugs incase ther incorrect as wrong loom
 
Hi,no luck yet,been busy week didn't have much spare time to fix it, massive thanks for diagram that should help alot
 
Jumped opposite polarities doh

Hey Romas,
Did you fix it yet?
PM sent with link for wiring diagram ;-)
Matt[/QUOTE]

I jump leader my bat the wrong way please tell me I've tried a fuse is there another relays fuses apart from the one under drivers side. Thanks in advance
 
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