4 lo not engaging 2008 automatic TRD sport

Hi I did a quick search with no results.

Is there a good thread out there for trouble shooting 4 lo not engaging?

I dont do any offroading but I do engage it every once in awhile, last time being a couple weeks ago and it worked.

I tried it yesterday about a dozen times.. in neutral, coasting slowly, in reverse, coasting backwards, in 3 lo, 2 lo in drive backwards forwards every scenario I could think of with no success.
I did have it in 4 hi prior to this which it goes into as it should.

Im going to start with the obvious, check the connections and wiring on the transfer case and take it from there.

thanks in advance.

 

Sure is

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Thank you

I must be searching wrong I never seem to get any results

Is there a sticky list with common issues somewhere?

 

Nope.

90% of the time. Its limit switch circuit issue. AKA water got inside the actuator and corroded traces in the actuator.

100% have to test.
If you are sure the truck goes into 4H.
You can assume the issue is within the transfer case.

Why guess?
When you can test it all right there in the truck at the 4WD ECU at find out where the issue is.

 

I just thoroughly shot the plug at the transfer case with brake cleaner and it started engaging right away, looks like it was a contact issue there

thanks, definitely good info in that thread will keep it handy for future reference