Flashing 4WD indicator light

[Overlander367]

So I am having the blinking light issue on my 2001 4 Runner, after reading this thread as well 99SC's thread over at YotoTech, I was excited to pull the switches off the actuator and test those fully expecting to find my problem there, only issue is after a hour of trying to manipulate the wiring harness off I cannot seem to get it to budge, I have inspected, pulled, pushed, and squeezed everyway possible I can think of, anyone familiar with these and how they come off before I turn a 5 minute inspection into a half day wiring nightmare?

 

[Bad Luck]

So I am having the blinking light issue on my 2001 4 Runner, after reading this thread as well 99SC's thread over at YotoTech, I was excited to pull the switches off the actuator and test those fully expecting to find my problem there, only issue is after a hour of trying to manipulate the wiring harness off I cannot seem to get it to budge, I have inspected, pulled, pushed, and squeezed everyway possible I can think of, anyone familiar with these and how they come off before I turn a 5 minute inspection into a half day wiring nightmare?

There should be a squeeze tab on the connector. They get pretty gunked up so try spraying some brake cleaner in there and working the tab while pushing/pulling on the connector.

 

[Overlander367]

There should be a squeeze tab on the connector. They get pretty gunked up so try spraying some brake cleaner in there and working the tab while pushing/pulling on the connector.

Yeah that is what I thought, will try the brake cleaner, I have went all around this thing, squeezing anything that resembles something protruding, sticking a small screwdriver inside the holes, nothing, they may just be aggravatingly stuck and the brake cleaner may loosen, I cannot imagine them being this complicated with the success of so many people testing these without issue on their end, I am cursed whenever it comes to me and maintenance, lol.

Thanks for the suggestion.

 

[phattyduck]

Gotta find the tab, press the back side of it and do LOTS of wiggling, rocking, pulling and pushing. There is probably a lot of built-up grime in the connectors.

I have spent longer than I'd like to admit on those connectors myself...

-Charlie

 

[Overlander367]

How is everyone getting to the sensors on the top of the Transfer Case? It is an automatic so there is not enough room to get to it from the top, I removed the brace from underneath, and lowered the transfer case with a jack as low as it would go, still not enough room to get anything on there. Why do they have to add all this bullshit to make these so aggravating.... :wtf:

 

[Bad Luck]

How is everyone getting to the sensors on the top of the Transfer Case? It is an automatic so there is not enough room to get to it from the top, I removed the brace from underneath, and lowered the transfer case with a jack as low as it would go, still not enough room to get anything on there. Why do they have to add all this bullshit to make these so aggravating.... :wtf:

That's exactly how I reached all of my sensors. I think I had to use the correct size wrench to get the topmost sensor and double wrench it to get enough leverage to break it loose.

 

[Esolly84]

I am having a similar issue on my 01 SR5. 4wd light blinks nonstop. However when I push the 4wd button it clicks in and spins the front driveshaft. Then hitting the center diff lock button it clicks in and drives like it’s in 4. 4lo works as well, no matter what I’m in the light won’t stop blinking. Not sure if this is the same issue as everything seems to work but hoping someone has some insight.

 

[Bad Luck]

I am having a similar issue on my 01 SR5. 4wd light blinks nonstop. However when I push the 4wd button it clicks in and spins the front driveshaft. Then hitting the center diff lock button it clicks in and drives like it’s in 4. 4lo works as well, no matter what I’m in the light won’t stop blinking. Not sure if this is the same issue as everything seems to work but hoping someone has some insight.

The blinking light when trying to be in 2wd indicates that either the transfer case or the front diff cannot achieve the commanded state (or it doesn't sense that it achieved the commanded state). With the light blinking while trying to be in 2wd I would lift all 4 tires off the ground, put the transmission in neutral, and engine off try to turn the front driveshaft and spin one of the front tires. If the front driveshaft rotates without spinning the rear driveshaft then the transfer case is in 2wd. If you can spin one front wheel without the other front wheel spinning then the front ADD is disengaged for 2wd. If transfer case and front diff ADD are in 2wd state then you need to look at the position switches on the front diff and transfer case for continuity when closed.

 

[fourfive]

The blinking light when trying to be in 2wd indicates that either the transfer case or the front diff cannot achieve the commanded state (or it doesn't sense that it achieved the commanded state). With the light blinking while trying to be in 2wd I would lift all 4 tires off the ground, put the transmission in neutral, and engine off try to turn the front driveshaft and spin one of the front tires. If the front driveshaft rotates without spinning the rear driveshaft then the transfer case is in 2wd. If you can spin one front wheel without the other front wheel spinning then the front ADD is disengaged for 2wd. If transfer case and front diff ADD are in 2wd state then you need to look at the position switches on the front diff and transfer case for continuity when closed.

My understanding is that a good continuity reading shoulder be <1. For the transfer case switches, how high of a reading, above 1, would still be considered good? I'm assuming that a new switch would have a continuity reading closer to 0 & a switch that is several years old would have a higher reading? Other than a multimeter showing no continuity indicating a bad switch, is there an upper limit/value that would also be indicative of a bad switch?

 

[Bad Luck]

My understanding is that a good continuity reading shoulder be <1. For the transfer case switches, how high of a reading, above 1, would still be considered good? I'm assuming that a new switch would have a continuity reading closer to 0 & a switch that is several years old would have a higher reading? Other than a multimeter showing no continuity indicating a bad switch, is there an upper limit/value that would also be indicative of a bad switch?

I don't think there is a specification in the FSM, and I've always just set my multimeter to continuity when checking the position switches. I would consider 5 ohms when switch is closed to be excessive in my opinion.

 

[96RedRunner]

Page TR-17 of FSM states switches are of on/off type using continuity test.
Then "If operation is not as specified, replace the switch." is stated.
Majority of problems I've seen are don't use em lose em like the others.
I'd cycle the system a bunch before I'd pull them. The detent ball has to travel a bit
to switch state of switch on to off vice versa and the ball can hang up in the throat.

 

[Esolly84]

The blinking light when trying to be in 2wd indicates that either the transfer case or the front diff cannot achieve the commanded state (or it doesn't sense that it achieved the commanded state). With the light blinking while trying to be in 2wd I would lift all 4 tires off the ground, put the transmission in neutral, and engine off try to turn the front driveshaft and spin one of the front tires. If the front driveshaft rotates without spinning the rear driveshaft then the transfer case is in 2wd. If you can spin one front wheel without the other front wheel spinning then the front ADD is disengaged for 2wd. If transfer case and front diff ADD are in 2wd state then you need to look at the position switches on the front diff and transfer case for continuity when closed.

Was able to get it off the ground today to look at what’s going on.
Engine off, in neutral: spinning front driveshaft did not spin rear driveshaft. Spinning front driver tire spun front passenger tire in opposite direction.
Running in drive: both driveshafts spin, rear wheels and driver front spin at idle. All 4 tires spin with a little throttle.

No combination of 4wd button, center diff lock, or 4 lo changed anything.

So I’m guessing it’s stuck in 4wd and front diff is stuck in 4wd too? Not sure why both driveshafts spin while running but are independent when spinning the front.

Per the last owner the old transfer case actuator busted so he swapped in a whole new tcase, he gave me the old tcase with it. Also noticed the breather line that goes from the top of the tcase to the tcase actuator is disconnected, with the nipple busted off on the actuator. Not sure if that would cause any issue but something else I gotta fix now.

 

[Bad Luck]

Was able to get it off the ground today to look at what’s going on.
Engine off, in neutral: spinning front driveshaft did not spin rear driveshaft. Spinning front driver tire spun front passenger tire in opposite direction.
Running in drive: both driveshafts spin, rear wheels and driver front spin at idle. All 4 tires spin with a little throttle.

No combination of 4wd button, center diff lock, or 4 lo changed anything.

So I’m guessing it’s stuck in 4wd and front diff is stuck in 4wd too? Not sure why both driveshafts spin while running but are independent when spinning the front.

Per the last owner the old transfer case actuator busted so he swapped in a whole new tcase, he gave me the old tcase with it. Also noticed the breather line that goes from the top of the tcase to the tcase actuator is disconnected, with the nipple busted off on the actuator. Not sure if that would cause any issue but something else I gotta fix now.

With all 4 tires off the ground does the front driveshaft spin with the transmission in park? I forgot to add that to the checklist.

 

[phattyduck]

So I’m guessing it’s stuck in 4wd and front diff is stuck in 4wd too?

You are stuck in "AWD" mode (4WD unlocked), from the sound of it. At least it is a safe mode to continue driving in!

-Charlie

 

[Esolly84]

With all 4 tires off the ground does the front driveshaft spin with the transmission in park? I forgot to add that to the checklist.

In park front driveshaft will spin, spins rear shaft with it as well.

 

[Bad Luck]

In park front driveshaft will spin, spins rear shaft with it as well.

At a minimum the rear driveshaft shouldn't spin with the transmission in park so this is really throwing me for a loop here. The only other thing I can think to tell you to try is transmission in park/rear tires on the ground/front tires off the ground try to turn the front driveshaft. If the front driveshaft spins freely then I would suspect a problem with the front ADD actuator/circuits.

 

[phattyduck]

At a minimum the rear driveshaft shouldn't spin with the transmission in park so this is really throwing me for a loop here. The only other thing I can think to tell you to try is transmission in park/rear tires on the ground/front tires off the ground try to turn the front driveshaft. If the front driveshaft spins freely then I would suspect a problem with the front ADD actuator/circuits.

With an open center diff it will - in the opposite direction.

-Charlie

 

[Bad Luck]

With an open center diff it will - in the opposite direction.

-Charlie

It's been a few years since I've had to diagnose this on my Limited, but I'm fairly certain that the rear driveshaft was stationary with the transmission in park in every transfer case setting except neutral.

 

[Esolly84]

With an open center diff it will - in the opposite direction.

-Charlie

It's been a few years since I've had to diagnose this on my Limited, but I'm fairly certain that the rear driveshaft was stationary with the transmission in park in every transfer case setting except neutral.

This is my first yota with a multimodal transfer case so I’m trying to get a grasp of how it works. From what I’ve read online and in this thread it sounds like the transfer case is always sending power to both shafts. Clicking it in to “4wd” is “awd” and this is done by the Actuator on the front diff, then the center diff lock can be used for a true 4wd. Is that right?

 

[Bad Luck]

This is my first yota with a multimodal transfer case so I’m trying to get a grasp of how it works. From what I’ve read online and in this thread it sounds like the transfer case is always sending power to both shafts. Clicking it in to “4wd” is “awd” and this is done by the Actuator on the front diff, then the center diff lock can be used for a true 4wd. Is that right?

Power is only sent to the rear driveshaft in 2wd. 4HI the transfer case sends power to both driveshafts but they can spin at different speeds. 4HI Locked and 4LO the transfer case sends power to both driveshafts and locks them together like a traditional transfer case forcing them to spin at the same speed.