OBD Port to ECU wire diagram

Hello I’m new here. I’ve owned a couple 2nd GEN 4runners but This is my first Tacoma. Its a 2004 2WD SR5 4 door. I bought the truck as a full offroad project. Previous owner was relocating battery and fuse box to the backseat and i believe deleted one of the wires from the OBD port to the ECU. I’m pretty sure it’s pin number 7 in the OBD2 port i just can’t find a wire diagram to find out where it goes. (Now the truck does start and run) only issue I’m having is trying to plug a scanner into the OBD port. It gets power and ground, but no signal to the ECU if anyone has a wire diagram that could help me out I would greatly appreciate it. I’ve been trying to surf the Internet for one but haven’t had any luck

 

What engine and transmission do you have?

 

sorry i should have specified. Its a 3.4 v6 auto trans

 

Thanks dm93!! That confirms that the solid white wire from pin 7 in the OBD2 Connector is missing. It shows that it goes to a junction and then into the ECU. It looks like it’s pin 14 in the E5 plug of the ECU. does that seem correct? Im not a wire wizard so i just wanna verify I’m not missing anything

 

Yea your correct, I wonder if someone did a swap at some point otherwise I don't see a reason it would go missing.

Can you get the part number off the ECM and VIN off the truck to see if it's the one that belongs to the truck?

I can look at diagrams for other configurations later and see if that pin is in a different slot on other engine/trans/year configs.

 

That did the trick. OBD is working! Thanks for your help man you rock!
I know the plan was and still my plan to swap the auto trans for manual but as far as I know it’s the same ECU that came with the truck. I can send you pictures of the ECU and the vin if you’re just curious and want to see

 

You can if you want, I'm just curious why the wire is mysteriously in the wrong spot.

 

Here they are. also, do you know if this ECU will still work after swapping for a manual transmission? I heard the 2nd GEN 4runners when you swap the 3.4 into them if you’re running a manual, you have to have a manual ecu but I don’t know if it’s the same going the other way. I’m hoping worst case I can just get the computer flashed or something

 

Looks like it originally came with a 3.4 A/T and the ECM is correct so not sure why the wire was misplaced.

Yes you would need a manual ECM to manual swap it, there's a guy on here that can "convert" some of the 2nd gen ECMs to work with a manual but I don't think it's possible on 1st gen ECMs

 

to your knowledge do you know if you have to swap the harness as well? if I get a mechanically shifted four-wheel-drive transmission Would I be able to just slap the ECU from a manual in without changing the harness?

 

I don't know what would be involved as I'm not too familiar with 1st gen trucks, the ECM pinout appears to be the same between 2wd auto and 4wd manual but I can't say for sure. Now if your truck has Traction Control/VSC (rare option on 1st gens) that would certainly complicate things.
Also 2wd manual would certainly be different since those don't have electronic throttle control.