A750F / A750E P2716 wiring harness short FIXED!

@bobsuruncle,

Turns out the connector you highlighted was a just a tube with a breather on the end and came off with the transmission when it came down. However, just about two inches below that was another harness retaining clip that was a pain to get to. A large flat blade screwdriver was able to pop it off the bracket while reaching up there from behind the transmission.

On a not so good note: bad news for me on this job, I broke the bell housing on the transmission when trying to pull it off.0 I missed a bolt that I could not see behind that thick harness. ... :-(
New housing on it's way from California now....

 

Well today I replaced the internal harness and no more 2716 code.

 

holy thread revival Batman. So second response to this post had your answer all the while...

 

I should also mention I replaced the slt solenoid while I was in there. After looking at much documentation relating to the valve body and showing pictures of how the internal harness is routed, I noticed that my harness had been routed wrong and was pinched between the filter and the valve body, which you wouldn't be able to see once the filter is installed.

I can't visually see a break or nic where it would be exposing a wire susceptible to shorting. Didn't notice any burnt or melted plugs or wires. I changed the slt solenoid mostly because when I compared one to the other, the one that was in my truck was missing the partical screens over the ports on the solenoid that I felt would allow debris to enter the actuator and potentially cause it to interfere with normal operation. I haven't done a resistance test on the old solenoid yet to see if it possibly failed.

So far it's been 6 days and approximately 300miles with what I feel is normal shifting/operation and no CEL has returned.

Now I'm struggling to get used to vsc kicking in since before it was disabled due to the CEL condition. My 06 doesn't have a buttom to disable it.

 

Well shit. 2716 is back. 2wks and not even 500miles. I went out to my truck and turned the ignition to accessory, engine off, and about 5 seconds later my ultra guage signaled a trouble code and CEL iluminated on the dash. Tried to clear it but it came right back. Only code present.

 

If you have the harness disconnected at any time the key is on , you will get a code as well
http://www.rostrapowertrain.com/typ...a&transmissiontypes=a750e-5-spd-rwd-2003-2016

 

So, this code just came on for me. I'm at 62k miles on my 2016 Tacoma 4x4 OR 6AT. Any tips or suggestions for me before my service appointment this Sunday? I'm worried the AT fluid is low as well, I plan on having them check this while there. This is all sounds like its going to be get pricey. Thanks in advance!

 

You should be on warranty ?

 

Nah, warranty ended at 60k, how convenient right?

 

Dealerships are known to call the transmission bad rather than fixing the problem .
Even if the issue is an easy fix , they tell you that you need a new trans $$$$$$

I guess you have a couple options .

1- Call Toyota corporate and open a case number . This will help when you bring the truck in .You are over the warranty period but not by much
Phone: 800-331-4331
Fax: 310-468-7814
Mon - Fri: 5:00 am - 6:00 pm PT
Sat: 7:00 am - 4:00 pm PT

2- Call around to one of your local transmission shops to see if they are interested in trying to eliminate the code .

3- Tackle the code yourself .
You will need some tools as well as a digital volt ohm reader .
I am sure I can walk you through the diagnosis .
Do you have the factory service manual for your truck ?
Send me your e mail ...I have a booklet to help you out .

 

Did anyone ever figure out a fix for this problem? I replaced my slt solenoid and code went away for a day or two. Now it’s back next move is to replace harness I guess.

 

Funny that this post gets a hit as I'm researching it further currently to move ahead with the repair. From what I've been told, 99% of the time solenoid faults are due to wiring connections in the harness and not the solenoid itself. In my case the problem lies at the female plug of the valve body wiring harness.

See here for an example of what happens in this thread.

I'm going to attempt and fix my wiring harness this weekend with a spare plug that came with the wiring harness on my junkyard motor.

 

I have not tried the Rostra harness yet on the A750 series trans , but I have used this company for years with other transmissions and their products are of good qualtiy

 

Bobsuruncle...let me know how it goes. Gearcruncher also recommended the harness from rostra which is probably the route I’ll take and just replace whole thing.

 

Will do.

 

Well found my issue rather quickly once I got the black cover off the plug. The pin go so hot in melted the plastic around it and burnt up. Pin #14, SLT+.

 

Awesome find !!!!
I have those male and female pins somewhere in the shop lol .
Make sure your grounds are freshened up . Thats what usually causes this

 

Added 2 layers of shrink wrap to the wires to help reinforce them. Time to start cutting into the main harness! So much for waiting till this weekend. I decided to go ahead and splice my replacement plug in, all the pins on my current plug looked worse for wear.

 

That took a bit longer than I wanted. Final splice done, just need to put some loom around it and tape it up.

Got it all back together and NO CEL!!


One thing for anyone attempting to splice a new plug in, make sure your wire stays at it's fullest length. I got in the zone cutting and splicing and heatshrinking that I didn't notice I started getting shorter with my splices. Another thing to pay attention to is there are 2 yellow with black stripes wires and 2 brown wires. These are pin specific and can't be mixed up. I noticed this before I made my first cut, but completely forgot about it when I got the cutters in my hand. I ended up having to refer to the FSM wiring diagram and find which wire came from what pin at the ECU to what pin at the trans plug. I used a tone tester to trace the wire and was able to get it back to it's correct place. I spliced each half of the plug at a time. Spacing the splices out just past the one before it so there wouldn't be a big ball of connectors in one spot. Took about 10" or so to stager them. I used plenty of heatshrink so I shouldn't have a problem with water entry.

I definitely suggest pulling the harness out and up to the engine bay, it made things much easier. It helps to have the wiring diagram of the ecu to transmission just in case you find yourself wondering which wire goes where. I probably could have completed this quicker but got ahead of myself and forgot to slide the heatshrink on before I connected the wires, and had to redo some a few times.

 

Great write up . A lot of work !!!
I laughed a lot , not at you , but with you
I have been there . Ford trucks are a wiring nightmare . On any given day of the week on the assembly line if they run out of blue wire , they change to a different colour . A nightmare to figure out
Its a needle in a haystack fixed