There's this from purefjcruiser.com/docs

https://www.purefjcruiser.com/docs/2007%20Toyota%20FJ%20Cruiser%20Repair%20Manual/A750F%20Automatic%20Transmission/Automatic%20Transmission%20System/0170018.pdf

more repair info

Dropbox

www.dropbox.com

 

This looks extremely helpful! The PDF has the precise debugging info I was looking for! Thank you!

 

Good luck with your troubleshooting ... given the previous rodent damage on your other vehicles and the visible presence of rodents on the FJ, I'll bet you'll find your problem will be the result of rodent gnawing.

There's a fair amount of positive recommendations from folks who have had rodent damaged wiring in the engine bay on the effectiveness of peppermint oil as a deterrent.

One correction ... no Toyota has ever used PTFE insulated wire in any chassis wire harness application. PTFE is used in a few limited places where there is exposure to high temperatures, like the pigtails on oxygen and air-fuel sensors. And the "soy based insulation" is really just standard polyvinylchloride (PVC) insulation where in some cases the plasticizer (very small % of the total insulation material) was derived from soybean oil.

 

There's a fair amount of positive recommendations from folks who have had rodent damaged wiring in the engine bay on the effectiveness of peppermint oil as a deterrent.

Could you provide more information about peppermint oil? Some links? Is it a spray? an open can? etc

 

Looking at this now... the A750F transmission connector is facing upwards, towards the transmission tunnel. Argh... To get to that connector, I'm going to need to drop the cross member and transaxle.

Wonder if I can pickup a connector from a local junk yard...

 

No idea what you are up to, but can you pull the shifter boots to get at whatever your wanting to get to?

 

I'm following the diagnostics procedure above on the 2nd post, isolating the possible wiring fault's location.

This involves removing the A750F B37 connector, which is located on the driver's side just above the pan to access the connector itself on the transmission (to test the SL1 solenoid resistance).

However, that connector is facing upwards towards the transmission tunnel - impossible to reach with an DVM.

There isn't any "shifter boot" to remove to access the top of the transmission. There's the transfer case's boot, but that's the passenger side. Looking above the connector, it's an all metal tunnel.

 

I traced the wiring harness to the back of the engine, and see no signs of cut wires.

I'm going to pull the ECU harness, and test the solenoid from up above (according to the manual). If it's stuck closed, then yeah it is the solenoid. However, if it's open with no resistance, then it still could be a cut wire.

It's 34F right now. So will wait for tomorrow.

Stay tuned!

 

Reading some other threads, the dealerships say to replace the transmission with a solenoid goes bad.

I don't understand that statement though. Looking at the manual, the solenoids are in the valve body. Will look into servicing that component without special tools.

 

Replacing the entire transmission because of a failed solenoid would be absurd. All of the solenoids are mounted on the valve body, are readily available from Toyota, are easily replaced once the transmission pan is dropped, and don't require any special tools.

 

Here's a pinout of the transmission connector.

There are two thermistors for measuring ATF temperature, and seven solenoids.

It will likely be easier to probe the harness for continuity and shorts-to-ground at the connector on the engine ECU, rather than the hard to access connector on the transmission housing.

I think the possibility that a solenoid has actually failed is just about nil.

 

Here's a pinout of the transmission connector.

There are two thermistors for measuring ATF temperature, and seven solenoids.

It will likely be easier to probe the harness for continuity and shorts-to-ground at the connector at the engine ECU, rather than at the transmission connector.

I think the possibility that a solenoid has actually failed is just about nil.

View attachment 1181391

Thanks. Yeah, the links in the 2nd post had the pinouts as well, along with the expected resistance readings.

That is my task tomorrow when it warms up again in the sun.

The think is, if it reads open... Then the coin is flipped between wire chewed or solenoid bad.

And you're right, chances of a solenoid bad is pretty slim.