Transmission shift signal

I have searched around I can't find anything on this topic

I'm going to be swapping a tdi engine into my 06 with the a750f trans. I need to know what sensors/signals tell the transmission to shift so that I can wire it up when the time comes. If anyone knows or can point me in the right direction please let me know.

 

Go with a manual trans or an auto that has already been mated to that or an auto that has lots of aftermarket support for swaps (4L60/4L80, C4, turbo 400 etc)

The A750 is controlled by the main ECU based mainly on accelerator pedal position and driveshaft output rpms.

 

I'm already able to get an adapter plate as well as a harness made to make the stock trans work. This way I don't have to get into doing driveshafts or anything. Longterm plan for the truck is a solid axle swap anyway. Not going for any more power then the 4.0 just more efficiency and cool factor.

I only needed to know which sensors tell the trans to shift and I'm ready to start on the swap

 

I suppose one could look at the white paper data on the A750 and see what solenoids are turned on/off for various gears and set that up to make an auto manual trans pretty easy and just set a static line pressure that was high and call it good.

 

I have that information but there's no reason I need to effect any of that. The plan is to piggy back the tdi ecu and the toyota ecu, since the toyota ecu runs the trans. In order to do that I have to figure out what sensors the toyota ecu needs to tell the trans when to shift so that a wiring harness can be modified.

Shift points and what not can be changed by a tuner with the toyota ecu

 

So on the transmission wiring diagrams I've found show only the throttle position sensor and engine Coolant temp are required. But looks like the temp sensor can be bypassed and eliminated.

But the other diagrams I've found which refers to the 1uz-fe with the a750f and shows more sensors required. I also found the same diagram for the fj cruiser and the only difference shows the fj doesn't require the engine coolant temp sensor

So now with this info, anyone have tacoma specific wiring diagrams showing the same information?

 

I don't see any way to get something like this to work as the PCM uses alot of engine parameters to control the behavior of the transmission, a Diesel is much different than a Gasoline engine in terms of load calculation.
The stock system uses mass airflow, RPM, and throttle position to calculate engine load, not sure how you would fool the Toyota PCM into working off the sensors on the Diesel.
Anyway here's the diagram tree for the A750F in the Tacoma.

 

My understanding is the tdi will give the toyota pcm the signals it needs and shift points, pressure, torque converter lock can all be changed with the toyota pcm. I'm working with a guy who's done lots of wiring harnesses for various tdi swaps and he believes we can make it happen. Absolute worse case I can use a compushift standalone tcm.

 

Well keep us posted, definitely something I've never heard of being done before.
Here's the wiring diagrams and Cam/Crank waveforms if you need them.

 

Best I can find is a controller by HGM.
I don’t even know if it will work for what you are doing.
But they claim the the controller is stand alone and is available for the A750

But……You can’t get one. Supply chain shortages.

I also kind of posted this for the other guys.
They might find it interesting. All said, I can’t say I’d do the swap you are looking at.


https://hgmelectronics.com/pages/toyota-lexus-a750-transmission-controller

Harness for A750
https://hgmelectronics.com/products/toyota-a750-harness

 

Never mind my above post.
Looks like you already know about them.

 

I know about this

 

Thanks that helps. It doesnt seem like its been done. Have yet to find anyone whos done it

 

I wonder if CANBUS can be used to solve this. I don't know all that much about how exactly it works just that it's how multiple ecus can communicate. Both the tdi and tacoma ecu have it I believe

 

AFAIK the only thing the Tacoma PCM talks to via CAN is the Skid Control ECU for Traction Control function and on the newer trucks (2012-15) it also talks to the Combination Meter via CAN.
Vehicle Speed signal comes from the Skid Control ECU through the Combination Meter to the PCM so that signal won't be an issue but I don't know how the rest would be accomplished.

 

Our trucks ecu uses analog signals to gather the information from the engine, correct?

 

Depends on what year. E.g., 2005-11 uses analog signal to drive coolant temp gauge in cluster but switched to CANBUS in 12-15 models like Dm93 says above

 

My trucks an 06. Forgive my ignorance in some of the earlier replies. I didn't know there were multiple ways vehicles communicate, CANBUS, analog, UDS and whatever other ways. I thought everything worked the way analog works. The earlier years would be analog for all signals or just some?

The guy who will most likely be doing my wiring harness and has helped me understand a lot of this. He has a device which converts signals to different "languages" (I guess correct word?) So the device can convert the CANBUS signals from the tdi ecu to either analog or uds depending on what's needed and vice versa

 

It still was a digital signal it just was transmitted on a separate line.

Virtually all communication signals on a vehicle are a digital squarewave, the voltages vary by system but it is considered a digital signal.

Some sensor signals to the PCM would be considered analog such as temperature and accelerator/throttle position, on these the voltage varies based on the output of the sensor.
Typically 0-5v max (0.5-4.5v valid signal range).
So on a coolant temp sensor for example 4.5v on the signal wire would typically translate to -40F and 0.5v would be somewhere over 250F on most systems with the voltage level changing in a linearly with temperature.

Other sensor signals like cam and crank position sensors would be considered digital although there are 2 basic types of speed sensor and each type generates a different signal.
For example if you look at the cam/crank capture I posted above you can see the signals look different.

The cam sensors are what's called a Hall Effect Sensor, this type uses a magnet and transitor that turns on and off when a ferrous metal passes in front of it. These generate a clean square wave (typically 0-5v) and have to be powered to function.

The crank sensor is a Variable Reluctance Sensor, this type of sensor is essentially a coil of wire that generates a voltage when a ferrous metal passes in front of it. These generate a sine wave signal and do not have to be powered to function.

The cam and crank signals have to be in time with each other or the PCM will either consider the engine out of time and set a code or won't know what to do and either shut off spark and fuel or fire things randomly.

 

If you go with the R155F the driveshafts from your A750f will work.
The A750f seems to fetch a fair dollar in the used market too, I was able to sell my auto for more than I paid for the R155f

I went down the same route you are going down wanting to retain my a750f with TDi swap, but in the end it would be cheaper to go TH400/4L80 if you are dead set on automatic, plus having much more selection of suitable convertors