Fuel pump issue

[Tuffy]

Hi guys. Hope someone can help me. Car was ticking over nicely on the drive on Sunday then suddenly cut out
 
Have traced it to no power to the fuel pump in the tank. Guessing probably fuel pump relay...which please correct me is located in the fuse box in the engine bay.?. Do any of the relays under the dash control the fuel pump? can someone just confirm relay number please?

Also any other ideas as to why power wouldn’t get to fuel pump...other than a broken wire?
Btw...have scanned and no codes present

Thanks in advance

[pudding]

Did you check the 15 amp fuse behind the side panel, adjacent to the steering wheel?  Think it's F27, but check your manual because internet information is sketchy at best.

Where did you test for 12V?  Before or after the pump controller?

There are 2 fuel pump relays, both are under the steering wheel behind the cubby drawer area.  1 is for the tank pump and the other is for the mechanical pump.  I believe they are the white ones taped to the fuse board, numbered 449, but as I say, have a look at the manual (Page 96 iirc) to confirm.

[Tuffy]

Thanks pudding checked  before a after the controller..... replaced relay 167 in the fuse box in the engine bay..... and swapped the two 449 relays round in the compartment under the cubby hole. I have my doubts if it’s either of them as the one that controls the fuel pump I believe also controls the interior light and there’s no issues there....
The 15 amp fuse appears to be fine too...
any other suggestion mate??

[pudding]

167 is normally the fuel pump relay number, but VW make changes frequently, hence why referring to the manual is a good idea.  I got the 449 info on the net ages ago when I had similar issues, but in my case, it was an failing pump so didn't need to bother with any relays in the end.

So no power to the controller?   There must either be a break in a wire somewhere, or the fuel pump relay is not being commanded on......in which case we need to look at the ECU trigger wire.   

Have you got VAG-COM?

Did you try bridging the fuel pump relay with a couple of spade connectors and a wire?   That bypasses the ECU and the relay and confirms power to the pump, and if still no power, it's a broken wire somewhere.

[Tuffy]

167 is normally the fuel pump relay number, but VW make changes frequently, hence why referring to the manual is a good idea.  I got the 449 info on the net ages ago when I had similar issues, but in my case, it was an failing pump so didn't need to bother with any relays in the end.

So no power to the controller?   There must either be a break in a wire somewhere, or the fuel pump relay is not being commanded on......in which case we need to look at the ECU trigger wire.   

Have you got VAG-COM?

Did you try bridging the fuel pump relay with a couple of spade connectors and a wire?   That bypasses the ECU and the relay and confirms power to the pump, and if still no power, it's a broken wire somewhere.
[/quote


At this point mate it goes above my head to be honest and I have to let my auto electrician take over😄
No vag just a generic snap on sonus which showed no codes.
Regarding testing the pump... he took a feed straight from the battery via a testing probe to the pump and it powered up.
That’s where my knowledge starts a stops
I’m just trying to get some ideas as he’s stupidly busy and can only call in when his passing

[pudding]

OK    I'm sure he will do some continuity tests and other bits and pieces.  At least the pump itself is working!

[Tuffy]

Appears to be mate. Just hope it’s not a fault in the ecu itself 😬

[pudding]

The ECU fault codes the pump relay normally, so the next test will be to see if the ECU is energising it.   Check for a voltage on pin 86 of relay 167 whilst cranking.  If there's a signal there, it's gotta be a break in a wire from the relay back.   That's a long wire, so will be fun tracing that!

[Tuffy]

Thanks for that mate. Will update when we trace the problem 👍🏽

[Tuffy]

Bit of an update. Nothing worse than searching for a solution to a problem ... then after four pages it hasn’t been updated with the solution.

It’s all pointing to a intermittent fault with  the fuel pump control module that lives on top of the fuel pump under back seat. (Small black box) it’s not sending the correct signal to the fuel pump.

Anyone else had this issue??

[Octoparrot]

It's not an unknown problem and I think VW have revised the part, search on you tube for humble mechanic fuel pump module which explains about the way they fail.

[ROH ECHT]

Was going to say the code for a relay isn't because there isn't a relay...it is for the controller just mentioned. I had the code once and went off searching every fuse diagram for every MK5 build period just to find there wasn't a match to my actual fuse and relay layout.

Anyways, I found there is no relay and the problem was with the controller. I replaced it and added a Torqbyte PM3.

But yours seems to be sorted now. Yes, it has been revised a number of times...mostly due to overheating and causing engines to quit running momentarily. Her they're showing the revision has reached "H"; 1K0-906-093-H...replacing D, E, F, and G. I have the "G" because the "H" doesn't work with the PM3.

[Tuffy]

Thanks for that....haven’t ordered one as yet.. how much are they from TPS?.

[Tuffy]

Ok guys.... the sarga continues... replaced the control module and still not starting... we have all the relevant power coming in before the control module and coming out.
If we power the pump via a probe direct from the battery it will prime.... connect the plug back into the top of the pump again turn the ignition  it doesn’t 🤔😡.

Although the pump primes when powered directly from the battery could it still be faulty?
Could the control module be picking up a problem with the pump and preventing it from running

Running out of options now other than trying a new pump..... just odd that it primes when powered by a direct feed

[pudding]

It's looking like a pump is the next step really.  The direct 12V feed from the power probe would run it flat out, whereas the controller varies the current according to ECU demand.  Perhaps the pump is just old (worn commutator) and unresponsive to the controller? 

Only other thing it could be is a dodgy pin in the controller-to-pump plug?