2015 Toyota Tundra Parasitic Current Draw- Body ECU wire?

Hi all,

I've been troubleshooting a parasitic current draw for a few weeks now. I've narrowed the draw down to the MET-B 5A fuse and ECU-B1 7.5A fuse. Decided to focus on ECU-B1 since that was drawing the most power (~150mA).

I then narrowed it down to one single wire connecting into the driver side J/B. Lower wiring harness, pin #13. It's a grey wire (will show images at the bottom).

Anyway, I went through and unplugged every single wiring harness under the dash, in/around the steering column, everywhere I could find to try to locate whatever module/system is causing the draw, no luck. So I decided to just cut that grey wire and see what happens.

Once cut, the traction control light, airbag light, and seatbelt light all came on. The key fob won't lock or unlock doors (but inside door lock buttons work), seatbelt light remains on when I fasten the seatbelt, and the following codes came up:

C1201
1. Engine control system malfunction
2. EV control system malfunction

C1231 Steering angle sensor circuit

C1241 Low or high power supply voltage

B1650 Occupant classification system malfunction

I don't think its the steering angle sensor, since I removed every wiring harness around the steering wheel and it made no difference. So I'm still trying to figure out where that damn grey wire goes!

Also as a note, while troubleshooting I did get a random check engine light for P0500 Vehicle Speed Sensor. I cleared it and it didn't come back (though there is still a (Permanent) code on there for P0500)- Unsure if that's related to anything or not. Before & after grey wire being snipped, no change in the vehicle speed sensor error code, so thinking unrelated.

Unfortunately I don't know how to read wiring diagrams. But what I've gathered is page 630 has the drivers side J/B. It shows pin #13 on the bottom harness, which is the culprit (labelled DB). On page 626 it shows the Main Body ECU, and it appears to show 13 DB being connected to BECU (Body ECU)??

But I'm no expert here, so I could be completely misinterpreting this.

Also found the last image which might show the wire in question?? Seems like its connected to ALOT of things. Where do I go from here?

 

The other end is the ECU-B1 fuse.
It affects a lot of things..

You could have pulled that fuse over cutting the wire..
Sorry, I'm not much help.



The seat belt is also tied to the door locks and SRS..


SRS is air bags


There are several more.

Good luck..

 

Haha, yea- The first thing I did was pull fuses. I knew it was ECU-B1 from the start, that's what led me to finding the grey wire on #13, as I narrowed it down from Fuse -> Harness -> wire. Now just trying to figure out what the wire does!

Seems like this grey wire is connected to a lot of things... Oy. Now how best to go one-by-one and figure out who the culprit is?? That's the question.

 

150Ma is pretty high.
I was messing with mine a month ago checking for a parasitic draw and found it was less than 30.

I'd guess the wireless door lock and garage door opener are always looking for a signal, so that's some draw.
Not sure what else.

Good luck..