2005 tacoma code P2714 on 4x4 w auto A750F tranny

Seeking some talented input for repair path forward, probably wiring / controls. After little use from running condition w ~60 k gentle miles, found hard to shift. ODBC Tacoma code P2714 seen. No lift at home n getting older so had reputable local transmission mechanic replace solenoid ‘D’ or SLT / linear selenoid, twice, with new parts, then transmission valve block. Same issues, still, one 0771 code in between which cleared. Tranny internals n fluid showed free of shavings - no clues to issue. not feeling confident full transmission replace will resolve ( plus collateral concern w corrosion etc underneath as 2005).

Thought at first it was ‘limp mode but can force it to shift - appeared to happen when warmed up a bit by running / higher rpm’s and good bounce from speed bump or pothole? Getting harder to shift and mechanical tranny inspection / repairs not prompting clear next step.

Suspect electronic wiring but that not local repair guys strength. NO signs of mice chews, loose junctions etc…this solution eludes 40 yrs of dyi skills w basic mechanical n electronic issues. Live on island in VI so local help pool very small. Help

 

Looks like it's a rationality code that sets because of transmission slip, the SLT Solenoid controls line pressure so it seems you may have a pressure loss somewhere or the pump isn't supplying enough pressure. Has line pressure been checked with a gauge?
@gearcruncher any thoughts?

 

Thank you DM93 for the quick reply and attachment with test sequencing n details! boy do I wish you were the tranny guy here! Doubt the pressure had actually been checked - thinking now that just the SLT and valve body swapped out based on the error code. Very useful lead - hearing about a next guy with actual pressure test gear, recent training n more experience so will search him down. Only hope truck remains semi drivable from first shop. Many thx for your time n input

 

Transmissions are not really my forte, I'm more the electrical diag guy. @gearcruncher is our transmission guy, he has a writeup on the A750 transmission here.

Based on the description of that code the transmission is slipping so I wouldn't want to drive it too much until you find out what going on.

 

Sounds like it may be slipping. That code is trying to tell you the turbine/output shaft speeds don't "agree". Solenoid and valve body have already been tried, if the wiring checks out it might need a tranny

 

Hey guys .

The first thing that comes to mind if I understand him correctly is a wiring problem .
If he hits a bump and the truck trips the code , its a good indication there is a wiring issue in the linear solenoid circuit .
Considering the truck is a 2005 , there are a few service bulletins that should be looked at .
Punch in your VIN number and see what you can find https://www.toyota.com/owners/

The case connector where the wiring goes into the transmission is incredibly well known for causing issues if the truck lived in the salt .
Not that great of a seal between the transmission wiring harness and the transmission case bulk head connector .
Guys who take thier truck swimming run into these corrosion problems often .
Although the link below is for code PO -2016 , it will give you an idea of what this member went through trying to find his issue .
The connector would be one of the first things I would be looking at
https://www.tacomaworld.com/threads/a750f-a750e-p2716-wiring-harness-short-fixed.527281/


2005 had an issue with the frame that use to cause the wires going to the transmission to stretch
https://www.tacomaworld.com/threads/05-motor-mounts-failed-failing.21849/

Were there any resistance checks performed before either solenoid was replaced ?
That part of the disgnostic tree will usually tell you if the wiring is good . A wiggle test with the dvom connecetd .
The pdf file posted above is a fantastic tool for helping to diagnose your code


Need a better idea of what was done to the valve body .
I agree that a pressure gauge would also be beneficial at this time .

 

Shouldn't that set a P2716 instead of or in addition to a P2714 though?
The way I understand the code descriptions P2714 basically means a transmission component slipping and P2716 is a SLT Solenoid circuit problem.
Apologies if I'm off base here.

 

Are you sure there isn’t a leak or the fluid is not low?
I did a bit of research, and these codes can be thrown when fluid is low.
It can also be thrown if the pump is sucking air. Which can be caused by a bad seal on the pick up.
Or…..let’s hope not, a bad pump.

 

No , i dont think you are off base . You are spot on in an ideal world when wiring is new and not all corroded .
I took into consideration that when he hit a bump , he lost communication to the solenoid and then i focused on green death in the connections . We all know that corrosion can create unusual codes and this doubles with hot and cold soaks .It seemed logical at 5 in the morning lol .

A pressure gauge would really answer some questions here or was a pressure gauge even used ?
Although low mileage , the seals inside the transmission are close to 20 years old now ,so a mechanical slip is also viable . The code triggers after 2 instances .
You would think if the transmission was slipping , the transmission shop should have fealt something from the drivers seat with a live data scanner connected . We are unsure of the scanner they used
A reputable transmission shop should have followed the same diagnostics as the pdf so I am trusting they did check for resistance .

At this point in time , all we can do is wait for more answers .

 

I do believe there was a TSB on the internal harness at some point?
But I can’t remember what the symptoms were. I could look later tonight.

 

There was a tsb for the external harness but that effected the neutral safety switch .
It's in my write up somewhere

 

That may be the one I’m thinking about.

 

Your comments align with symptoms n suspected cause. Very appreciated. Working to retrieve truck back first from ‘best Tranny guy’ on island later this week after he **hopefully** at least returns to the semi running state to drive away - next week (things are manana here). Pressure test, resistance, troubleshooting protocols - nah…grrr

had done basics to look over external harness junction for looseness, corrosion, bent pins etc before shop visit but visually no issues noted - had difficult tracing circuit back towards ECM and no continuity checks at that time. Suspect that needs revisit based on Gearcruncher’s input - wanna travel to VI

Some frustration in hindsight with current knowledge that after some coin and 6 months of persistence to even get in his cue, learned his experience n habits excellent on the mechanical side but almost nil on the thoughtful troubleshooting and technical steps forward. Seems to be strictly hardware swap outs, communicates little and resents input, says does not do wiring - after conveying multiple times that codes need several cycles to appear, still not reflecting he grabs that. Not trying to talk shit about him as well earned reputation in some aspects, have found now that his habits will not resolve this. Just trying to retrieve in semi whole state, first. Small island, limited options.

THANK YOU for steps forward. Will get back to you

 

All, thank you for your experience and such willingness to share. Very grateful. hope this thread helps someone else.

Issue is now resolved and wanted to share that fix turned out to be replacement of two bad speed sensors for $220 on the transmission exterior top sides (plus labor etc) - no need to even drop the tranny pan etc, regardless of ODBC codes indicating selenoid function as most likely issue. friend located a set of retired mechanics doing stuff in their yard who have the $ laptop / software and actual recent training w step wise troubleshooting. They accomplished in one week what 6 months interface with the transmission shop missed. Go figure.