When I park my truck the battery in my D2 has started to drain much faster than anticipated, especially because I’ve got a larger group 65 battery.

I connected a multimeter and saw a 100 mA drain with everything off and I know the spec is 35mA max so I started unplugging and reseating fuses. Most had no effect until I unplugged F2 then it dropped to 44mA, it stayed there even when I plugged it back in.

What does F2 power?

I also unplugged my under seat cd changer and found the plug to be corroded and it looked kind of melted and the draw lowered again (to the magical 35mA). I suspect water got in down the B pillar and caused some damage to it. I have an aftermarket head unit installed so I insulated it up and am going to keep it unplugged.

 

The 15A fuse F2 in the engine bay is part of the Engine Management System of the ECU.
The electrical systems included are the air injection valve, purge valve, camshaft position sensor, EVAP canister, leak detection pump, all the O2 sensors, MAF, SAI pump, & inertia switch.

 

Did your truck originally have air springs in the rear? If it did and the air springs were replaced with coils without the BCU setting being changed from air to coils the air springs pump can often continue to operate trying to level the truck. That happened with my truck and it has been reported by others. But it would seem odd for it to start happening suddenly if the air springs were replaced some time ago.

 

How do you test for draw with a multimeter?

I have one, but I am not very familiar with how to operate it. I've got a drain that I would like to chase down

 

So naturally it’s going to power the most electrically complicated systems in the truck! I’ve got a downstream o2 sensor that’s on its way out, so perhaps it’s that.

My truck (to the best of my knowledge) never had the air springs. There would be a button to raise them on the dash if it was ever present, right?

Testing was pretty easy and there’s actually a LR TSB on how to do it, I’ll try and dig it up. Essentially when you need to do is:
1) Disconnect the hood alarm switch (by the washer filler), I also removed the horn relay as an extra precaution as I didn’t want to deafen myself if the alarm went off plus I was doing this during the kids nap time.
2) Keep the hood open and close and lock the doors.
3) I disconnected the negative lead, set my meter to measure milliamperes and connected one side to the battery terminal and the other to the negative lead. The TSB says that the system should be powered the entire time so I think I screwed that part up because the second the lead is disconnected it’s powered off, I may have to build a custom jumper or something and retest.
4) You are then supposed to give the truck 30-60 minutes to ensure that everything has drained but I didn’t have time for that and I think my meter will auto power off before then.
5) I just started unplugging and re seating fuses and made note of current draw readings.

 

Here’s the link to the LR official test procedure:

https://landroverforums.com/forum/at...w_8601nasf.pdf