ECM location?

Jnickoles · Nov 7, 2023

Does anyone know where the Ecm is located on the 2021 tundras? Long story short, I snapped a bolt off in the frame and I’m going to weld a nut to it to back it out, but I’d like to disconnect the battery and the ecm first. I’ve tried searching all over, but all I can find is the location for it on the 1st gen models. It looks like it’s inside the cab with the wire connections under the hood, just wanted to confirm.

Jaypown · Nov 7, 2023

RainMan_PNW said: ↑

Got a Sequoia? We've got you covered (or will soon). Head on over to this thread.

Over the years, I've managed to find, download, and stash away a variety of different "complete" (or mostly complete) diagrams for various years of Tundras. Most of it has been a result of me wanting to "upgrade" something on my truck to be like a higher trim level or a newer truck year when I had my 2008 SR5 - things like installing the Optitron gage cluster, doing the Auto AC Climate Control upgrade, or even swapping out my 2008 JBL head unit for one from a 2010 in order to add the BT streaming audio and USB media port. Over time, I've come to get to know how these diagrams work pretty well, and have used the information to troubleshoot or tinker a lot of other things as well.

So, I'd like to share what I have...which now includes the complete set of Tundra diagrams. Some are more detailed than others - for example, when I recently pulled down the information for the 2021 (which also includes data for everything 2016+), I decided to pull down every single connector data sheet as well (there are 520+ of them). The PDFs I have here are not quite as user friendly to use as the live TIS site, but they are as functional as a single PDF file can be without me spending hours trying to actually hyperlink things the way the TIS site does.

The 2021 EWD contains all of the information for MY 2016 and newer (I focused on MY 2021, but made sure to include any EWD-specific pages that were for older MY's in the same group), with individual EWDs denoted by references such as "Before Aug 2017 Production" to indicate MY 2017 or older, and "After Aug 2017 Production" to indicate MY 2018 and newer (remember that production for a new model year typically starts around August of the prior calendar year).

General Manuals and Info:

2016-2021 EWD Introductory information (Applies to pretty much any EWD after 2005) - 103 pages

1991 - 2005 Wire Harness Repair Manual - RM1022E - 418 pages

2007 Wire Harness Repair Manual - RM06H0E - 459 pages

Gen 2.5 (2014-2021) Tundra:

2016-2021 Tundra EWD - EM27M0U

Covers MY 2016-2021

Separated into sections:

Introductory information (Applies to pretty much any EWD after 2005) - 103 pages

System Circuits (MY 2016-2017) - 497 pages

System Circuits (MY 2018-2021) - 654 pages

Location & Routing (MY 2016-2021) - 185 pages

Fuse Lists (MY 2016-2021) - 37 pages

Overall Diagrams (MY 2016-2021) - 195 pages

Connector Data Sheets (each sub-part includes a full index)

Connectors starting with numbers 1 through 3 - 56 pages

Connectors starting with letters A through I - 361 pages

Connectors starting with letters J through OQ - 505 pages

Connectors starting with letters P through ZZ, and any lowercase letters - 330 pages

Some other notes:
These are set up to use the bookmarks feature in most PDF viewers, and I have removed duplicate "source" diagrams where the same diagram is used in several different bookmarks (Cruise Control, Electronically Controlled Transmission, and Engine Control in the 2021 EWD is an example). This reduces file size, but will mean that if you just hit "print" on the whole document you will end up with something that may not be in the same order that as the list in the table of contents.
Click to expand...

Jaypown · Nov 7, 2023

Down on the Gen 2.5 section, Click on Location and routing. The first page of the PDF will help you out.

Jnickoles · Nov 7, 2023

Jaypown said: ↑

Down on the Gen 2.5 section, Click on Location and routing. The first page of the PDF will help you out.
Click to expand...

Awesome, thank you!

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