4wd light stuck flashing green (2018 trd offroad) **fixed**

Good call will do

 

Yeah I need to change it anyway so I'll do today.

 

No codes and it was first blinking my differential light and then sometimes within this last week it is now blinking the 4wd light which sucks. I'm pulling it apart today to check everything

 

You just copied someone else who posted about it being 4wd light not the diff and you act like I haven't searched and seen all those threads already

 

Thank you

 

It is almost certainly a limit (detection) switch in one of the actuators.
If the Diff lock light is flashing, you can not shift to 4WD. You can’t not run the diff lock in 4H. There for, you aren’t going to get it into 4H if the Diff Lock is messed up. (Flashing)

I’d start at the diff lock. Unplugging the connector and inspecting it would be a good start.
Although it’s likely INSIDE an actuator.

These trucks don’t do well at all if you have water intrusion into the actuators.
Us 2nd Gen guys have been dealing with this for years.
The 3rd gens are no different. They are just “newer” and haven’t had enough time to fail.

You 3rd Gen guys are lucky in one way.
At least you all have codes that can be read with a scan tool.
That’s a big help in diagnosing it.

 

Just an FYI, if your Diff is actually stuck in a locked position from actuator failure, you can absolutely shift into 4hi (still locked) and then 2hi (still locked). The diff lock stays lit, along with about every other light since it shuts off ABS, TCS, etc for diff lock, and does not turn off until unlocked. I had to drive about a hundred miles home locked in 2hi. Was fine on the freeway, SUCKED in town.

EDIT: I've got a 2nd gen, not sure how it works on 3rd.

 

If you want a better forum, you'll need to go back about 20 years. As for your issue, you got the solenoid wet, and over the last month a bit of corrosion has set in.

Remove the actuators and clean them.

 

If it is locked in 2H, then you switch back to 4H does it still work?

 

Yeah, the actuator for 4wd seems to function as usual. Can shift to 4wd hi, then low, then back to 4hi and 2hi.

 

There's a differential breather relocation mod posted on another tacoma trail site that I plan on doing to avoid any problems that I'm assuming are similar to what you're describing. Might be worth looking into, it's a cheap mod and looks easy to do.

 

I'm currently doing that now, so far there's the front diff actuator, is there one on the transfer case I need to check as well?

 

Changed all the diff and transfer case oil. Then pulled out the add and emptied the water out. Tested the actuator motor and it worked fine then the switch with a continuity tester and it was working fine as well. Put everything back and still have the green flashing 4wd on the dash

 

I can’t really explain how to test the 4WD ECU easily.
But the issue should be hard to find if you the ability to back probe the 4WD ECU.
A safety pin works ok for back probing.

The system is a pull to ground design.

I’ve included the link ECU data list should you wish to test your limit and signal switches.
https://www.ttguide.net/terminals_of_ecu-1470.html

It “looks” complicated. But it really is the “easiest” way to pin point the circuit with the issue.

 

FWIW: I don't see the "insult(s)" here.... But I did see some valuable advice: Standard operation is to never to drive in water that is deeper than half-way up the wheels. If it's salt water I wouldn't drive in anything deeper than the wheel rim. You stated you had water coming up over the hood. Very fortunate your engine didn't gulp a nice cool drink of any of it.

You dodged a bullet.

 

Use a 2 way breather, otherwise it will be a useless mod. Using a 1 way breather (like what is stock) will not prevent water intrusion when the diff cools off under water and creates a vacuum inside. You'll pull in water from the axle seals.

 

This is the breather, it's a 2 way

 

99% chance your ADD actuator got flooded and messed up. Very common, you can find a break down on the fix by searching the forum as it's happened a lot.

 

That's a 1 way breather per Dorman. Designed to match the design and function of the stock breather.

 

To double check, I put it in my mouth and air passed through both ways. If it is a one way, it's not very effective.