Stuck in 4 lo help

Wow that just went over my head pretty quick. I read through those and this is what is happening.

 

Im looking through the service manual and diagrams now. Trying to make a list of pins for you to test so we know whats what.

You will need to get to the 4WD ECU either way. Located up behind the glove box.

 

OK sounds good. Thank you!

 

4WD ECU should have two connectors on it. F13 is the large 40 pin, and F12 is the smaller 10 pin. This is a view looking at the ECU. Real world pic below, 4WD ECU is the black module in the middle. Careful of the airbag in front of the blower..

I recall having a hard time getting back there. If memory serves the 3rd gen glove box / surrounding trim removal would rival BMW stupidity. Might get lucky and just pull the glove box itself? But anyway



Below is with the connectors unplugged looking AT them. (Just for reference leave both plugged in for now)




Attached PDF is a guide to the 3rd gen t-case. First few pages give an overview. Pg 5 shows the Neg lead of your DMM will be on a solid chassis ground point, and the Pos lead will be used to carefully backprobe the indicated F13 pins. If you take a reading and jot down the voltage at each pin on Pg 6 we should know where everything is.

 

Looks like someone is on their way to do a 3rd gen 4wd system writeup

 

Here is one I started in 2018

https://www.tacomaworld.com/threads/4wd-actuator-troubleshooting-transfer-case-and-add.578262/

Sorry, wont be able to dig in and help much more than this tonight, but tomorrow will have alot of time

 

Looks pretty good so far, I did one on the 2nd gen system which looks to operate about the same but I went with voltage checks instead of resistance as that's what the ECU sees and is more reliable.
I don't have a 3rd gen to study so I couldn't say what voltage its using but most sense circuits are either 5v or 12v, when the limit switches are closed you would see 0v.
The nice thing about the 3rd gen system is it's ability to communicate with a scan tool, that makes troubleshooting 10 times easier as you can see exactly what the ECU is seeing without the need to backprobe wires to check voltages.

 

Any updates?

 

fyi, i don't think have to take off the entire glove box to access the ECU. you can just take the cover off the cabin air filter access hole. I have to take my filter out and remove the leaves once a week since it's parked under a tree and I can see the wiring going to the ECU.

 

Sorry guys for the late update. We got 3+ feet of snow over the last two days.

I was able to ask a favor and get it into a trusted local shop. He scanned it this morning and the motor on the transfer case actuator had failed.

Currently standing by to see what they recommend next.

 

i imagine you will need to replace the actuator. they got one on rockauto for $133.49 (aftermarket) or you can get an Aisin for $182.79

 

That sucks. At least you know what it is now. I'm wondering if the shop couldn't put it into 4hi for you, put the failed actuator back on or cover any holes a removed one leaves behind, tie up the writing, and then maybe you could at least have a drive-able truck until you can get parts and they can put the new/rebuilt unit on the truck. Just a thought.

 

It's about upping post counts. Quantity vs quality.....

 

I think so too. I mean the OP is stuck and needs help, not some stupid ass comment about parting it out. There is a time and thread but not here. I see the Mods cleared it up.

 

I'm glad you were able to determine the problem. Hopefully that shop can get you fixed up soon and for a reasonable price.

 

Thanks for the update. Glad they were able to figure it out.

 

I'm a little skeptical of that. These don't fail *unless* they get water in them from a disconnected vent line.

I would have liked trying manually powering the motor with a 9v battery. But either way, sounds like youll be up and running soon so thats good

 

He did test the motor and said it would not work.

Not the bill I was hoping for right before Christmas but should back up and running by next week.

Thank you to everyone who reached out and helped on this thread. I really appreciate it.

 

Update-

Replaced the transfer case actuator and it’s back to normal operation.

 

The AnyTime Locker Install video is up!!!

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