battery drain - F27 and F13

[lionel1972]

Hi,

I have a 2008 golf 1.9 tdi (engine code BXE) which has a battery drain problem. I think I have traced this down to 2 fuses using a multimeter and testing the voltage drop across fuses whilst the car is in ‘sleep’ mode.

The 2 fuses are:
F13 in fuse box B (engine compartment) and is 10A
F27 in fuse box C (interior, to right of driver’s instrument panel) and is 20A

I have checked the owner’s manual in the car and F13 is not listed – anyone know what this is for? The fuse box is ‘Type A’.

F27 says it is for the fuel pump, but the manual says it should be 15A (not 20A which I have). I took it out and tried to start the car and it wouldn’t fire, when I popped it back in it started immediately…I have no knowledge of how a fuel pump works but it sounds like this could be it, but not sure if removing the fuse would have an instant effect, surely there’s some fuel in the system that would fire?
One thing that puzzles me is that when I took F27 out the electric rear windows also stopped working (which is F26 according to my manual). There was a clicking noise but the windows did not move.

Can anyone shed some light on these 2 fuses?

Thanks,

L

[Guest 2]

F27 is definitely 15a and supplies the;

J17 - Fuel pump relay
J538 - Fuel pump control unit
G6 - Fuel system pressurisation pump
J643 - Fuel supply relay

F13 comes back as a 30a fuse supplying the;

J623 - Engine control unit (diesel)
J623 - Engine control unit (petrol)

If it is the 'Low' version.

If its the 'High' version F13 supplies;

J743 - Mechatronic control unit

again 30a.

[lionel1972]

Thanks Chris.

F13 - I'm don't know if I have the high or low version, but I suspect it is the low version as a quick search on "Mechatronic control unit" looks like it is for higher spec cars - how do I confirm for sure? My 10a fuse is quite under-rated. I need to look into what the Engine Control Unit does but the car started and ticked over fine when I took the fuse out, does that seam plausible?

F27 - all fuel related, which makes sense from what happened when I took out the fuse. The fact that my rear windows stopped working looks strange.

[Guest 2]

Mechatronic control unit if you have a DSG gearbox.

[lionel1972]

OK, today I had my local VW garage read the fault codes, it came up with 8 pages of faults but I think (hope) that many of these are because I have disconnected the battery and taken fuses out:

05377 P1501 Fual pump relay short circuit to ground
12545 P3101 intake flap motor open circuit / short circuit to ground
05660 P161C Glow plug cylinder 3 open circuit
05269 P1495 EGR cooler switch-over valve open circuit / short circuit to ground

Can anyone offer any advice on any of these codes?

[Guest 2]

Why didn't you have a look at our VCDS User Map? http://www.google.co.uk/url?sa=t&rct...58187178,d.ZG4

012545 - 19559/P3101/012545 - Ross-Tech Wiki

05660 - P161C/005660 - Ross-Tech Wiki

05269 - Help with a code
Suggesting brake light switch?

Can't find the other two.

[lionel1972]

Thanks for your help. The VCDS user map looks great - I'm new to this so what's the done thing?

I found out that by joining my local VW garage's loyalty scheme I get 30mins free diagnostics, which was a start to get the codes read.

MY progress on the issue so far is that I took F27 out and let the car go to sleep and then checked F13 to see if there was still a battery drain, and there wasn't...so rightly or wrongly my conclusion is that something on F27's circuit is to blame. It was interesting to see the Fuel pump relay on the fault code as your info suggested fuel pump related items, I've read that the relay is underneath the dashboard, do you know which one it is? Do they go wrong, or is it more likely wiring?


The fuel pump relay is the one I'm keen to find given that it was the fuel pump fuse that