Where is the fuel pump relay ?
 

can anyone tell me where the fuel pump relay is on Audi A6 2.5 tdi ( 2001 )

I'm not getting a live feed from fuse box to fuel pump in the fuel tank. is there a relay between the battery & the fuse box that I can change/check ?

thankyou

I've found the realy & tested it & all the other & they are all working fine.

I'm not getting a live feed to the 20amp fuse which is the fuel pump fuse. any ideas why there's no power to the fuse which feeds the fuel pump?

thankyou

you check the connections on the back of the relay?
sometimes the wiggle and bend and either open up or break all together.

if the wire looks fine then stick a multimeter or some other kind of current tester through the wire and see if the wire itself has power. if it does the connection inside the relay housing is dissconnected somehow.

thats all i got.

Are you getting a live feed to the relay? No live feed to the relay follow it back.

Check the electrical diagram for that fuse. Normally the fuse feed is from a wiring block...you want the fuse as close to the supply as possible to protect everything downstream, including the relay.

thanks for the input guys.

I think I know what the issue is now, got a guy coming out to plug in computer to see if my theory is right.

hope it all works out, been pulling my hair out over this one :(

whats the theory?
and keep us updated, someone else is bound to have this problem in the future.

Well my theory is this:

When my car went into limp mode at first I had no idea to what the problem was, first thing I done was check the fuel filter & to my horror it was full of water, I removed the fuel filter cleaned it all out & replaced it, the car was running fine. I went out to buy a new filter & on my way home the car stopped as if it had ran out of fuel so I organised a tow truck to get it home. I removed the filter again & it was full of water again so alarm bells started ringing in my head & the first thought was the fuel pump had packed in due to the water. After ages spent trying to remove the fuel pump from the boot I hooked the motor up to my battery & it was fine! While the fuel tank was open I decided to remove all the diesel in the tank, remove pipes from filter & blow them through with my airline from back to front, loads more water! replaced fuel pump, filled up with fresh diesel replaced filter hoses & tried to start it but nothing!
Bled the injectors, loads more water & air pumping out, after a while nice clean diesel was coming through.

After some more head scratching it was time to check power supplies to fuel pump & you guessed it, no power to fuel pump, no power at fuse & none at relay ( I tested the relays, clicking fine & clean )

So i'm sat in the drivers seat & bang it hit me ( or so I hope, not been tried yet )

The heater plug light ( yellow coil on dial cluster ) was flashing & I knew it never flashed before, it would come on for a few seconds & go off but not this time it was just flashing! so out with the handbook & it turned out it's engine management.

Now my theory is that all this water in the fuel system was a bit to much for the old girl so it goes into limp mode, then engine management decides that it's had enough & shuts off power to the fuel supply hence no power to the fuel pump.

I'm hoping & praying that my car has gone into a self protection mode to prevent damage through so much water & gunge being in the fuel, fuel lines & filter.

I've got a scanner coming today to reset engine management & hope that I regain power to the fuel pump, if it does then things should start up & run like a sewing machine again.

I will come back & let you know the result, fingers crossed

So there's the whole picture from start to hopefully finish :-)

Be back soon

The mechanic has been today & plugged the car into his computer with 3 codes showing as:

01318 Control module for injection pump sporadic-no signal

01318 Control module for injection pump (J339) No communication

17978 Engine start blocked by immobilizer: P1570 -Static- No indication on display

Are the top 2 codes related to the immobiliser ?

If I got the immobilizer sorted at Audi main dealer would that fix the problem ?

Thank you