Stuck in 4low

My 2005 4.0 automatic is stuck in 4lo. (Green) 4x4 and (yellow) 4lo lights flashing. What to do?

 

I got a 6 spd..may be different but I just shifted around a bunch turned the knob a bunch of times ....forwards 10' backwards 10' a few times and got it to reset ....

 

There has been an issue. When you crank the truck up and it’s in 2wd the 4x4 light always flashes no matter what. And after the truck warms up while going down the road the 4lo light starts flashing. And you can’t put the truck in 4x4. If just the 4x4 light is flashing you can switch the truck off put the selector in 4x4 turn the switch and you can hear it engage and the 4x4 light stays lite no flash

 

if it's flashing it's not engaged. only engaged when the light is solid.

perhaps your switch is broken and it can't fully switch out of 4x4? weird that your 4LO would just start flashing on it's own though.

 

Check your limit switch voltages as outlined in the thread below and post your results.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

That looks like it’s going to take hours to do it and I don’t know how to. Any help?

 

Mine was mechanical, in the transfer case actuator.Water intrusion.
First i checked and tore apart front actuator, nothing there. Either way you have to troubleshoot..
Doing what @Dm93 suggest gets the answer quicker.
Or you can tear everything apart like i did and hope you get lucky.

 

https://www.tacomaworld.com/threads/how-to-trouble-shoot-4x4-actuator.263525/

here is another thread i used..

 

It's not difficult to do, figuring out the pinout is the hardest part but all you need is a basic multimeter (helps to have a ground lead with an alligator clip) and a small backprobe, sewing needle, or T pin.

Your other option is to start taking things apart (taking care to note the timing of things) and hope you get lucky.

Since you have both the 4wd and LO lights flashing I'd suspect the problem is in the Transfer Case Actuator but it could also be a wiring issue.
You can also crawl under the truck and check the vent hoses on the actuators, if one is missing or detached then odds are that actuator is the problem but it's not a guarantee.

 

I checked the voltage at the ECU and can’t find any voltage on some wires according to the charts you posted. Thanks. Where else to look? Both actuators have been replaced.

 

Do you have your results?
Without knowing what the voltages are I can't do much to help you other than tell you to double check the timing on the Transfer Case Actuator, that's why I made the voltage chart so it could be printed out and filled in because the only effective method I've found for diagnoaing this system is checking the inputs at the ECU and comparing them to what they should be and where the actuators actually are to help pinpoint the issue instead of shotgunning parts at it.

You are far from the first to replace both actuators and still have a problem, the cheaper aftermarket actuators tend to be quite problematic, alot of times people get the timing incorrect when they reinstall the Transfer Case Actuator, and the problem isn't always one or both of the actuators but instead a wiring problem.

 

There are two plugs that plug into the ECU is there a specific one I should test?

 

All of the limit switch circuits except LO and 2-4 (don't really need to test these since your 4wd selector switch appears to be working) are on F13.