4WD indicator blinks rapidly when returning to 2WD

Hi gang,
My 2010 Tacoma has been flawless in 4WD for all of its 127,000 miles... until I recently ran through the 4WD (High and Low Range) modes, plus the locker... just the monthly routine.

The truck goes in and back out of high and low range just fine. But, when it is returned to H2 (2WD) the indicator showing the truck is in 4WD, plus low range, plus locked, blinks rapidly. I am in 2WD, however. I go back into 4WD, shut the truck off, etc. and the light goes out.

This has happened twice now.
Any ideas?
I searched but didn't see the same problem. As I say, it goes into and out of 4WD, low range, and the locker works fine. Just the indicator stays on and blinks rapidly when I go back to 2WD, not the normal blinking if the transfer case isn't engaged.

Thanks for your suggestions! @Speed Freek
David

 

Sorry to hear of the troubles.

I am much more knowledgeable on 3rd gen, but will try to help a bit as much as I can.

[Edit. 2nd gen 4wd ECU doesnt communicate with CANBUS, so techstream is of no help]

In addition, help me make sure I understand some things.

Can you describe a bit more in detail when the dash lights become unusual, and when they appear normal. Chances are you have one (or more) bad position feedback indications to the ECU (from ADD or the Transfer actuator, or the transfer case signals). It will help to point which position sensor is likely going bonkers if you describe when the lights become incorrect, and when they still seem normal...

If you go 2wd -> 4hi: does this cause any issues, is the 4wd indicator normal and truck in 4hi
If you go 2wd -> 4hi -> and back to 2wd: does this trigger the issue?
If you go 2wd -> 4hi -> 4low: there are no apparent issues, all normal lights (4wd and 4lo)?
If you go 2wd -> 4hi -> 4low -> 4hi: are there any issues apparent on dash?

 

Thank you for helping Ted!

I will try the various points you name.

What I did do, in both cases, is go from H2 to H4, that was normal.
Then go to L4, again normal. Then lock the rear, normal.

I then reversed the steps and returned to H4 (normal) and to H2, but THAT is when the indicator began flashing rapidly rather than turn off. Now, I drove and turned my truck to confirm it was in 2WD (no binding and not in low range).

It took me a couple of tries to get the light to go off... turning the truck off, putting it back in H4, etc.

I will document it better.

 

Sounds good.

I would definitely try going from 2hi to 4hi and back to 2hi as a final test... see if that also causes the issue. If so it should helpfully narrow it down to my guesses.

Otherwise I would then switch to using an ohmmeter to check the feedback signals.

 

@BigWhiteTRD @Speed Freek : I just went through all the combinations into and out of H4, L4, Rear Locker and back to H2... three times... and the rapid blinking did not happen... Maybe just posting on Tacoma World fixed it!? LOL

I will let you know if it happens again and, naturally, would like other Tacoma owners to post if their 4x4 indicator blinks rapidly when they return to 2WD, as mine had.

 

As said, I am not a 2nd gen expert, but i would maintain the problem is 99% likely a feedback sensor (or wire/connector).

But it seems like it is probably not one of the ones that primarily are used to control power to the actuators, and is instead used just to provide feedback to the ECUs.

Going to have to wait for it to return to diagnose it.

(My wild guess is on one of the stand-alone switches in the transfer case)

Good luck

 

It is just weird... I live in San Diego County, about 280 feet above sea level, so there is no snow driving needs for me, lol!
I was mostly concerned for when this Covid nightmare ends and I return to Baja for camping on the beach... That is where I use 4WD the most! I may not be doing any more extreme 4x4 trails as I get older? Mission Santa María is still a hoot to drive!
Do see it in an upcoming Amazon Prime TV show episode... and the producer asked me to provide historical notes injected into the show (as I have been to that mission 4 times and I wrote the book about the missions). Here's a 2-minute preview of 'The Last Mission':

https://youtu.be/y4e0CC8HLk4

 

So far, all is well!
I drove it for 10 miles in H4 on a wet, straight road (for the monthly recommended lube). Then I went through going into and out of low range and the locker three times. I have not been able to repeat the rapid blinking issue. All is well on my 11 year old Tacoma!