4WD issues AGAIN. Advice needed

Ok guys here’s the situation. 08 DCSB TRD OR, I start the truck and the 4WD light(the green one) starts flashing. 4WD will not engage. No clicks from the computer behind the glove compartment no mechanical noises from the actuators. Normally the answer is the ADD actuator I know. On to list of parts I’ve changed recently.

ADD actuator twice this year so far(second one was under warranty for the first one)

Both sensors on the top of the transfer case.

The E-locker actuator($900 fml)

E-locker sensor.

Only things I haven’t replaced at this point are the transfer case actuator, 4WD switch, and 4WD computer(almost never go bad).

Looking at this as a computer science guy I’m thinking when I start the truck, the 4WD computer checks the system(sensors) for errors, returns true or false and if errors, then flashy light and high blood pressure.

So my question is where do I start now? I’d like to think that I haven’t burned a 3rd ADD. Is there a sensor on the front diff I haven’t changed? Bad connection on one I’ve changed? New sensor gone bad already? And before everyone says “fj case swap”. I know, I want to. I lack the time, mechanical aptitude and cash for that right now. It’s on the list behind supercharger. Any guidance, advice, wisdom or (serious)suggestions are appreciated. I’m so mad about this right now I’m ready to sell it and buy a ford.
Thanks in advance for the input guys. In addition to costing me a fortune, Tacoma World has always been a fantastic resource and very helpful.

Update: Fixed! Took the ADD actuator off, disassembled it and dumped the water out for starters. Thing was nasty and corroded inside. That factory seal is a joke. Cleaned it up, soldered the connections covered them all with dielectric grease and then put that thing back together with an excessive amount of RTV. It will NEVER leak again. Working flawlessly now.

Think this might have been my issue? Damn thing is 6 months old.

Note for future TW members with this problem. Actuator is a bitch to get out. The process is made so much easier by loosening the diff mount. It allows just enough play in the diff to make removal possible. Also don’t forget Your breather hose. Be gentle removing it and don’t forget to reconnect.

 

Are you starting the truck with it in 4wd? More than likely it's the transfercase actuator.

 

No. Sorry should have added that. Starting in 2wd.

 

I dont suppose you have soldered the motors on the teansfer case and front actuator have you?

Also do you happen to have the part numbers for the two switches on the transfer case?

 

I have not yet. Since the first one was under warranty I met Toyota replace it for free. It’s kind of a pain to remove. I don’t happen to remember the part numbers but I can dig for them again if you need them.

 

Going through the proper procedure to get it into 4wd. Not trying to sound like a smart ass. Also sometimes mine will flash and beep and if I pop it into R or D it'll lock in the gears just need to get lined up.

 

Yeah I could use the part numbers. I have read a lot on the forums that soldering the electric motors in the transfer case and ADD can helpnbeef up these 4wd systems reliabilty. I'll be doing that myself this summer along with replacing those switches in the transfer case I inquired about.

Good Luck with your 4wd!

 

sell all the electronic junk and put an FJ case in there, your life will be much happier!

 

3 things Toyota did away with on their trucks they shouldn't have.
1. Manual hubs
2. Manual transfer case shifter
3. Solid axle

 

OP, I know you said you are comfortable with computers but are you also confident using a VOM meter? If so post back and I'll send some diagnostics your way. Its best to tag me so I will see.

 

@ovrlndkull I am aware of the proper procedure for getting into 4WD. The light starts flashing when I start the truck while it’s in 2wd. From there I get nothing from the switch. Thank you for the input though. Sorry if I was unclear.
@kidthatsirish Beck Arnley

$19 201-1788 Back-Up Switch

201-1788. I forget if it was one in the tcase or one in the locker actuator had a slightly different connector and was a different part number. The tcase takes at least one of those though. I’ll have to hunt down the other one again.
@taco09 I’m no electrician but I can test for continuity. I’d love some diagnostics.

I crawled under it and pulled the connectors off the tcase sensors and then stuck them back on. Seems to be functioning fine now but we’ll see how long that lasts. Intermittent issues are the worst.

 

@88Taco
Check your PM.
Holler if you get in a jam.

 

Agree,these days the Toyota electronic 4x4 system is complete junk.

 

Right, I swear it takes me 10 minutes every time I switch into 4WD and engage the rear locker just trying to figure out the secret code.

 

Try getting into 4x4 when you are going uphill in the middle of nowhere,and the darn 4x4 takes forever to align up in order to go into gear,no thanks.

 

Truck is fixed(has been for a while actually, just been too busy to post). Thanks to everyone that contributed. Updated original post with the fix.

 

For sure,now they IFS system is nothing but complete junk.

 

I don't think it's junk. I think people just don't follow the user manual and use the system every month like they should.

I use mine every month and never had any issues after 170k miles until the dealer hit it during my frame swap. After I fixed the bad limit switch it was good to go.

 

It think the IFS system (ADD actuator notwithstanding because it is junk) is actually pretty decent. Yeah it’s not a solid axle with a manual t-case but for the wheeling I do I like flipping a switch and being on my way, and manual hubs are just annoying. If I were a hardcore rock crawler I’d have a Jeep or the like with solid axles. But for a daily driven weekend warrior, I love my Taco.

 

well you're lucky. I'd say its a 50% crap shoot whether the electrical crap will work for you or not. Def not worth the risk of keeping the electronic components.