So a few months back i bought a complete 3.4 manual out of a 98 4-Runner. Now my 3.4 harness has three connectors for the ECU, and then two for the dash harness. Now looking at the ecu, it has a forth connector on it. Why is this? Did I miss something out of the donor truck?

Going to start my wiring process tomorrow after work. And the fun begins

 

My truck 92 Pickup 4x4 manual..
Donor 98 4-Runner 4x4 manual..

just a fyi.

 

Does it look like this?

 

yes it does.. i will take pictures when i head out to the shop tomorrow. but yeah three connectors plug in fine, and the two dash plugs have be cut so i can solder them up to the old 3.0 dash plugs. but i'm not sure why it's empty.

 

Been a long while since I dropped in the 3.4, but I distinctly remember having one completely un-used plug.

 

Had the same problem. I was missing the 22 pin connector on the right. I cut the 22 pin plug off of my 3.0 harness and wired it up.

If memory serves, it only has 7 or 8 wires going to it, like power, switched power, starter, A/C and ground.

I think. Sorry for being vague, but looking at my diagram, that is plug A (E5) and those are the functions on my '97 Taco ECU.

 

hrm.. well i know it's not with the engine harness because i got the whole setup with nothing cut... i'm wondering if this connector by it's self maybe running to the fusebox or something.. if so i'm going to need to head back to the yard, which i got my donor engine from, and clip the plug if it exist..

 

oh i found your posting on the subject matter. i know i've seen that picture before. talk about research. lol what a pain

https://www.yotatech.com/forums/f160...77/index2.html

 

No, no...I know it's not on your 3.4 harness. It wasn't on mine, either. I cut it off my 3.0 harness and used it for that plug on the back of the 3.4 ECU.

 

yes i understand it's not apart of the engine harness. i'm hoping i still have my old ecu plugs from my 3.0 laying around. i didn't count on this coming up. always something near the end.

 

It comes off the body harness from the doner rig. Your obd 2 port uses that plug. So if you ever want to be able to communicate with your ecu to check codes.. you need it wired up.

 

+1.. sounds about right...

 

Here a terrible snapshot from my camera phone. as you can see i'm missing the 28 pin connector. I checked my old ecu from the 3.slow and found out that it did not have the same plug used. =( Looks like i'll be heading out to the bone yard tomorrow in search for this plug.

 

ECU PIN OUT

 

I found the diagram of the mystery plug.

 

Oh, it looks like they switched plugs after my 97 model. Mine are all just two row plugs, not those multi-row ones like yours. Sorry, dude.

 

Super Duper! always something right....