4wd System Operation & Help Thread

If you have 12v at the ECU on TL3 (Blue/Black)
Then you have a bad path to ground.
Do you have 12v at that wire on the plug for the ACTUATOR with it unplugged? (check it at the actuator on the transfer case)


And if you have continuity through the actuator with it unplugged, and in 4LO position, then the issue would be wiring up to the ECU.
Or from the actuator on the White/Black wire to body ground.

Checking the Blue/Black wire at the actuator with it unplugged, will verify wiring from the ECU.
If you see 12v. The wiring is good. If not, you have a break in the wire to the ECU.

 

Yeah i just checked and I have 11.75v on the plug between blue/black and black/white at the actuator.

 

Ground TL3 at the actuator connector and verify it goes to 0v at the 4wd ECU.

 

Yeah it goes to 0v when I connect the lines and back to 12 when I disconnect them.

 

So it would seem the issue is with the contacts in the actuator, have to take it apart and have a look just take care that the gear stays in place so you don't lose the timing.

 

Ok. Yeah i'm currently looking for the post or video I ran across the other day about doing just that. Should have bookmarked it damn it.

 

This thread helped me when i needed to tear apart the transfer case actuator.
some good pics in case the gear pops out.

https://www.tacomaworld.com/threads/4x4-issues-front-diff-actuator-or-t-case-actuator.358059/page-3

 

Finally managed to get it off. It looks mostly decent but there are two grooves in the 4H position on the rails that it may be warn out or not be touching? Hmm

 

Doesn't look too bad, clean it up, maybe tweak the contacts a bit so they are for sure contacting the plate, put it back together, and see what happens.

 

Thats exactly what i did. wiped it down and spread a thin layer of the grease around. bent the pins down a bit further and then put it back together. She slipped back into 4h and then into 2H like there was never an issue. Thank you guys so much for the help, that was a fun problem to hunt down and i really appreciate the help.

 

Does 4L work too now?

 

Yeah, I put it through each gear and back again a few times just to check and it has switched smoothly each time.

 

Nice, glad it all worked out
I'm assuming since you had it off you checked/replaced the vent hose as well?

 

Yeah I snipped the tip off and it fit back on much more securely. Might look at it some more and replace it if its an issue.

 

Has anyone tried / had success reconditioning the contact pads in the transfer actuator, maybe by cleaning out all the grease, then flowing a thin layer of solder onto them?

No issues with my transfer actuator at-present but wondering if that's possible.

 

Ok was just checking because the vent hoses cracking or coming off is a common cause of actuator failure. Wouldn't hurt to check the vent hose on the ADD Actuator as well although it's alot less common to break since it isn't as exposed but there is a spot where a hose clamp could potentially rub a hole in it.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/page-17#post-28163684

 

I don't think it would be worth the effort, if they got bad enough that the plating is flaking off I don't think there would be a way to make it reliable again. Typically that only happens when moisture gets in from a bad vent hose.

 

I have been reading this post for the past few days enlightening myself to fix the blinking 4x4 light on my 15 Taco. This post has been very helpful. I have replaced the front ADD actuator & a Transfer Case Switch with no luck of getting it to stop blinking. The original witch I did Continuity test on and it had none when depressed.

I have taken the voltage measurements & I need guidance to fix this issue before the snow flys.

Thanks in advance.

 

Unplug the front ADD Actuator and see if you have 12v on the Light Green/ Black wire with the Key ON.

It is pin #3.

--- I don't suspect it to be the ground wire (White/Black). As DL2 is being pulled to 0v. It uses the same ground wire --- (For those that want to follow along)

 

When you replaced the ADD did you make sure the shift fork engaged the collar in the differential correctly?