Fuel Pump Primary Circuit Malfunction the engine management light come on then goes into limp home mode but I have changed the fuel lift pump and the relay. But still getting the code up and I have put a live feed to the lift pump and iam still getting the the limp home mode. Any ideas what it could be or what I could try. I have had the problem for months and its getting worse. It used to only go into limp mode when there was less than half a tank of fuel but now it's doing it every few miles and doesn't matter how much fuel is in it etc.

What year is the car? What engine code (ASZ or BLT)?

What reader has been used to get "Fuel Pump Primary Circuit Malfunction" info, and what fault code number was that?

Hi car is a 2005.... BLT engine, not sure the make of the reader. I can find out later tho and the fault code was p0230.

That's enough info for me to have a look at wiring diagrams for you. I suspect the problem may be a damaged wire from the engine ECU to the fuel pump relay, rather than from the relay to the pump.

Will check at lunchtime.

Ok thanks would you think it would be a good idea to get an auto electrician out to have a look and see if the problem is electrical? 

Possibly, yes.  It seems very likely that it's electrical to me. 

Ok thank you I will get onto one asap then thanks 

Wires that may be relevant:

 

Brown wire from pin 4 of fuel pump connector should go to chassis/earth/battery negative.

Blue/white wire from pin 1 of fuel pump connector should go to one end of fuse 61

The other end of fuse 61 comes from the output terminal (87) of the fuel pump relay in position 4 of the relay panel (red/yellow wire).

Terminal 30 of the fuel pump relay holder should have a permanent 12V feed (red wire).

 

High side of the fuel pump relay coil (85) comes from the output (87) of the ECU relay in position 15 of the relay panel

Low side of the fuel pump relay coil (86) comes from a blue/red wire on pin 80 of an 81 connector at the engine ECU.

 

This last one is possibly the most vulnerable to damage as it is thin and passes through from engine bay into the scuttle area, most of the way along that, then through the firewall connector behind the wiper motor, into the cabin, to the relay panel.  If that wire is corroded due to an insulation crack and water ingress, it may be that the fuel pump relay isn't being energised reliably. Recommend a continuity/resistance check of that wire early in diagnostic investigation.

 

 

Thank auto electrician is attending on Wednesday so I will get him to check the last one first. 

Thanks again 

On 01/05/2019 at 13:25, Wino said:

Wires that may be relevant:

 

Brown wire from pin 4 of fuel pump connector should go to chassis/earth/battery negative.

Blue/white wire from pin 1 of fuel pump connector should go to one end of fuse 61

The other end of fuse 61 comes from the output terminal (87) of the fuel pump relay in position 4 of the relay panel (red/yellow wire).

Terminal 30 of the fuel pump relay holder should have a permanent 12V feed (red wire).

 

High side of the fuel pump relay coil (85) comes from the output (87) of the ECU relay in position 15 of the relay panel

Low side of the fuel pump relay coil (86) comes from a blue/red wire on pin 80 of an 81 connector at the engine ECU.

 

This last one is possibly the most vulnerable to damage as it is thin and passes through from engine bay into the scuttle area, most of the way along that, then through the firewall connector behind the wiper motor, into the cabin, to the relay panel.  If that wire is corroded due to an insulation crack and water ingress, it may be that the fuel pump relay isn't being energised reliably. Recommend a continuity/resistance check of that wire early in diagnostic investigation.

 

 

APols for resurecting old thread. I have this error code intermittently (although it has appeared to be increasing in frequency).

 

I want to try the free tests first, namely test restistence/continuity for the cable from the fuel pump relay coil to the Engine ECU. Are there manuals with diagrams avail to download, or dows anyone have pictures/photo's they could upload for reference please? I have seen a video on how to access the relays behind the imstrument panel but that is all I have found so far

Is your car a mk1 Fabia?

If so go here: MK1 Fabia workshop manuals - SKODA Fabia - BRISKODA

 

Download the file Fabia CFD MY2003-2004 and look on pdf pages 130 and 131.

It's not the perfect match to your slightly later car, but I'd be a little surprised if anything has changed between that and subsequent file versions.

 

References in rectangular boxes are to the track numbers where the wire continues. Track numbers are the ones beneath the horizontal line at the bottom of each diagram.

 

On 16/09/2021 at 16:01, Breezy_Pete said:

Is your car a mk1 Fabia?

If so go here: MK1 Fabia workshop manuals - SKODA Fabia - BRISKODA

 

Download the file Fabia CFD MY2003-2004 and look on pdf pages 130 and 131.

It's not the perfect match to your slightly later car, but I'd be a little surprised if anything has changed between that and subsequent file versions.

 

References in rectangular boxes are to the track numbers where the wire continues. Track numbers are the ones beneath the horizontal line at the bottom of each diagram.

 

This issue mostly disappeared not long after I reported it. it would randomly reappear occasionally but would usually go away again after restRting the engine.
Now however it has started to appear again much more frequently (More than half the journeys).
I have removed the lower dash and can access the relays there. I have also downloaded the manual you pointed me to but I am not sure what I am looking at. To make matters worse I am colourblind so am unable to see which wire is the brown wire referred to earlier in the thread.
What do you guys need from me, to be able to assist further? I can take photos of the relays if that helps

@wodgey The wire from the fuel pump relay (position 4 in the relay holder) to the engine ECU starts at a contact labelled 4 or 86 under the relay, and goes via an inaccessible connector deep behind the dash to pin number 80 of the 81-way connector at the engine ECU. The wire is blue with red stripe all the way.

Here's a view of what I guess is the mating face of the ECU connector in question, with pin 80 marked in red:

 

 

Marvellous thank you. I'll look at this Thursday when I'm off work