Parasitic Draw on Battery

I have a 2018 CM 1794 and had a couple of rough starts followed by a dead battery needing a jump. I had the dealer check it out and they said the battery was fine. I'm going to be towing a trailer in a few days so I wanted to get to the bottom of it. Have about a 0.5 amp draw and found the circuit. Anyone know what ECU-DCC is? See pics below. Thanks!

 

ECU should be your computer. Curious has you isolated it to that.
Are you getting you meter in the loop for current measurements?

 

Pretty sure. I pulled a bunch of other fuses and the amp meter didn't budge. Pull that one and it goes down every time. The only thing I could think with the ECU is that I have a pedal commander but I didn't think that would affect the ECU.

 

The PC shouldn't be the issue but you should eliminate it as a possibility. I would remove it for a quick check anyway, you never know.
2018 still under warranty? If so maybe dealership time.

 

I was afraid of that. I did find that it’s hard to get an accurate reading because the truck knows when the hood is open and will display it on the center screen. Kept the multimeter hooked up and closed the hood. Still a draw, but only 300 mA.

 

I’ll be interested to hear what this ends up being

 

Came across this for the ECU-DCC

https://www.tundras.com/threads/anybody-know-what-d-c-c-fuse-is-labeled-as-short.62483/

https://www.toyotanation.com/threads/battery-draining-after-1-2-days.327284/

Looks like a main to pull for transport mode.

 

I saw those posts, but the DCC in those cases is in reference to a short, not an actual fuse. I have a short as well (you can see its location in my first picture, above the 20 amp fuse that is the problem circuit). Maybe it is just a pull for long term storage, but I thought that was what the short was for.

 

So you have a fuse in Short and in ECU-DCC?

 

Correct

but the fuse in short doesn’t have an amp listed on it. I’ll try and snap a picture of it tomorrow

 

All that comes to mind for me with DCC is DC cut, I cant think of anything else at the moment.

Electrical gremlins man, take it to the dealer if your under warranty. I know it may not be ideal though.

Even 69mA I think is above Toyota allowable spec.

 

Ok, so new twist. I jammed a screwdriver into the hood latch to make the truck think the hood was closed. If I wait a few minutes without touching anything, the amp draw drops to 50mA. So no parasitic draw. BUT, as soon as a turn my engine over, it dies. Try it again and it turns on fine. Happens if I don’t drive my truck for more than an hour or so.

 

The Tundra's ECU draws a ton of power. My battery typically drains significantly in a week if the truck just sits.