Thread: D4 fuse?

Checking over the wiring of my 2013 D4 SDV6 HSE to see why my main battery voltage seems to be low ... considering it's a brand new AGM battery.
Engine off voltages measured around 11.9V - 12.2V and on engine start this voltage increases to 12.81V ... I thought it should be around 13.8V or thereabouts.

Opened the engine compartment junction box to check the alternator fuse (F20), which is in both the 'Car Owners Manual' and the 'Wiring Diagrams' pdf only to find that it's NOT there!!
The slot is there .. it's marked F20 .. but it has NO fuse and only one pin is seen in the socket.

Does anyone know if this fuse has been deleted/relocated to a different location now on this model ? Seems like there should be a fuse somewhere!
I did reset the BMS with the IID tool when I changed the battery over and as the exact capacity battery was not shown in the IID tool 'drop down' I selected one with slightly lower capacity rather than going higher. I wouldn't expect this to cause an issue though.

Originally Posted by rapserv

Opened the engine compartment junction box to check the alternator fuse (F20), which is in both the 'Car Owners Manual' and the 'Wiring Diagrams' pdf only to find that it's NOT there!!
The slot is there .. it's marked F20 .. but it has NO fuse and only one pin is seen in the socket.

It doesn't have one. In my D4 wiring diagram the batt sense fuse is explicitly called out as for the 2.7. The alternator on the 3 is controlled by a LIN bus ECU only and therefore doesn't have a battery sense line.