AlexMcGillivray

Quick update:

Cleaning the plug and socket didn't work, it looks like there is damage on the BCM board. Thankfully there is a Jag specialist with an electronics Wizz nearby so I'm going to whip the bcm out over the weekend and take it down there. They said it should be plug and play once they've re-pinned it but they want me to bring the car down after so they can re-pin the plug as well.
I should know in about a week if it's worked or not.
If not I'm guessing I'll have to fork out for a new bcm and programming from JLR main dealer.

Alex

1 hour ago, Jimbov8 said:

Hi Alex, here is the electrical manual for your car that will help you narrow it down;

http://www.jagrepair.com/images/Electrical/Elect-Tech All2/2012 XF - X250Comp.pdf

 I think this may be the culprit...
If I'm reading the schematic correctly, fuel sender return is a green/blue cable that is in the loom/plug at the bottom right of the rear junction box. and this is what i found inside it. Looks like liquid ingress at some point. I'll try and clean it up and let you know how I get on.

Thanks for all the help so far!
 

download.jfif

Happy Friday!

So bit of an update:

I've managed to get the engine codes read (I work away a lot so don't get as much chance as I'd like to work on the cars)

The breakdown was caused by P115A-00 low fuel level limited power followed by P115B-68 forced engine shutdown.

I've cleared the codes and the ones I'm getting consistently are:
P0460-15 Fuel level sensor A circuit - Circuit short to battery or open
P0460-1C Fuel level sensor A circuit - Circuit voltage out of range
P1346-15 Fuel level sensor B circuit - Circuit short to battery or open
P1346-1C Fuel level sensor B circuit - Circuit voltage out of range

Now to me that sounds like a broken earth/negative as that's shared for both circuits.
I've had the boot lining out briefly to have a look before it started raining, Would I be right in guessing they go to the fuel control module, which I'm assuming is the one behind the junction box with the megafuses?
Or does the negative simply earth to the body somewhere along the line?

-Alex

5 hours ago, Big John said:

Hi Alex

Have you looked for any stored error codes since the original problem?

Only other thing that I can think of is that the replacement pump needs to be paired or coded to the car.

Maybe this will help with the fuel gauge issue: 

Regards

John

Hi John, 

I've already cleaned the socket and main plug, removed small black plugs and hard wired them as recommended by Jag's technical bulletin JTB00301NAS1 from March 2014 (attached). 
The issue is not just that the fuel gauge reads low, its that the dash shows "Fuel pump system error" as well and has done with two different fuel pumps. 
I did look into the coding but according to JLR it's not a part that requires coding to the ecu or bcm.
I've spent all evening looking at wiring schematics and I think I've gone a little cross eyed trying to figure this out

JTB00301NAS1 - Fuel Gauge Operation.pdf

I've changed the fuel filter

Hi All, 

I'm at my wits end with this issue,

I've had an odd issue in that when the car was on idle for a while or in very slow moving traffic I'd lose power almost completely and barely be able to pull away. After getting up to speed (eventually) the problem would go away, I thought it might be the pump in the tank as that died and the engine stopped but there were no errors on the dash or codes to read.

I found there were a couple of corroded connections on the plug which I cleaned and repaired and that got the pump running again but it didn't seem to be moving fuel so I replaced the pump and managed to get the engine started and running again but now I get a fuel pump system fault on the dash.
I've checked the pump, applied the fix from the official jag bulletin about the small black plugs failing and still getting the error although the car starts and runs.
I've metered the sensors in the tank and they seem to be reading correctly as far as I can tell. I can hear the pump running to prime and when the engine is running but I still get the error and the fuel gauge showing empty. 
I'm concerned the in tank pump will cut out again as it has done once since it was replaced leaving us standing on the side of the motorway in the rain waiting for the RAC.

My next guess would be a broken or frayed wire somewhere but from what I can tell the cable disappears through the rear bulkhead into the boot.

I thought I'd ask for some advice before I start dismantling the car completely looking for a broken wire.

an help would be greatly apreciated

Alex