2002 with 4WD lights flashing nonstop

[RfirstToy02]

Hope to get some ideas with where to start on this. I have a 2002 4Runner SR5 with 180K on it. Had all 3 belts replaced a week ago because they were worn and squealing. Squealing stopped - Yay! Now fast-forward a week. I hop in on a snowy/slippery morning, hit the 4WD button on the shifter and the dash lights flash, as usual. But they won't stop, they flash ALL the time now. We've tried the tricks like acceleration/deceleration/reverse/figure-8's - and none of those quick tricks have done the job. Checked the fuse and it's fine. Disconnected the battery - that didn't work either. Waited a day to drive it, that didn't work either. Had to use it for work on Monday, and one minute I could feel the drag on the wheels as if it was in 4WD, and then on some tight turns there was no drag, so I'm assuming it's going in and out of 4WD at its leisure?? Also, I tried to use the cruise control, and it worked, and I think it was in 2WD then. But then after work I tried again, and the truck had obviously shifted into 4WD (can't turn worth a darn now) and no cruise control.

So a couple of questions... A few folks have mentioned to check for a vacuum hose(s) - and I found a diagram on a different forum, but I think it's for a 99' Runner, not an 02. Are the vacuum hose(s) inside the passenger's front fender somewhere? And, do you think a disconnected or cracked hose would allow it to go in/out of 4WD?? I do not have a Hayne's manual or anything like that, so if you reply with a description, please be very descriptive - or a copy of a diagram or picture would be most helpful!!

Second question - Does cruise control not function if the 4WD dash lights are flashing? I've read my manual in + out and there's nothing about a disconnect between the two - but I guess it could make sense... if you're in 4WD should you really have your cruise set?!

If you've got ANY other advice, shoot it my way, please. I'll admit, I'm a woman and pretty much don't know diddly about all this 4WD stuff, but I'm good with a keyboard and a computer so the hubby sent me on a mission to run the forums for help!! I've read lots about this problem and it seems it horribly time consuming and technical to diagnose this issue - some of them seem easy fixes, others are not. Something about an actuator or an ADD switch? Sigh. I love my Runner... but this is heartbreaking!!

 

[FancyPantsMcGee]

You are correct, this could be a real fiasco to troubleshoot. here's what I can tell you up front:
There is an actuator that engages your front differential when you press the 4WD button. It is in the upper left hand corner of the attached photo. It should have some vacuum hoses and an electrical plug going to it. Verify that all these look good. If the vacuum hose has come off I think it could cause you predicament. It may have come loose somewhere not immediately next to the actuator so get a nice flashlight and try to follow them.
the actuator and corresponding hosery can be seen here:

hope this helps.

 

[RfirstToy02]

Thanks

Thank you for the reply!! I thought I was all alone out here - so many folks looked at the thread but nobody replied. Now I can give my hubby a starting point! I'll be sure to come back on after he checks things out and give an update. Crossing my fingers for a loose hose!!

 

[JamesDean91]

Is the runner a auto or standard? Does it have multi mode(awd) or just basic j shift transfer case? I might be able to help more with that info.

 

[RfirstToy02]

James - Thanks for your inquiry. We have an automatic. But I can't tell you if it's multimode or J-shift. BUT... I do have a picture for you of our shifters. It's the best I can do for now... and yes, I'm quite embarrassed that I don't know the difference! I have a feeling I'm going to learn a LOT about 4WD in the upcoming weeks. If this pic doesn't help you to figure out what I've got, tell me what info I can give you. Oh, and it's my first time trying to attach a picture - hope it works!!

 

[JamesDean91]

Alright do you have the button on your dash next to your dimmer switch that looks like /-/
|
| - |
Anyways other then the multi mod having a short someplace I would look under the driver side at the transfer case there should be a blue plug with 2 wires going in and 2 going out, if there is corrosion on those connections I believe it will make the truck think the 4wd is engaged when it really isn't. You can unplug it first and see if it fixes any symptoms

 

[RfirstToy02]

Yes - I've got that button on my dash. So what does that mean... J or multi-mode?

Hubby will pull the truck in the garage tomorrow and start investigating. Thanks to you guys for your suggestions - it's a great starting point!!

 

[JamesDean91]

Multi mod you have a awd function and it seems as though something might be shorting or sticking in the 4wd system. In awd it shouldn't be hard to turn but when the diff lock is engaged (button on dash) it will be in full 4wd and be a pain to steer on the street.
By chance when you hit the 4wd button did you also push the dash button? I'm not 100% sure but if say the dash button got pushed by accident somewhere along the lines and then you hit the 4wd button something might have jammed. Try hitting the dash button then the 4wd button while in neutral.

 

[Singtoe]

I just went through this. Everybody's advice so far is flat out wrong. Even the picture they have is wrong. Pushing buttons and shifting to neutral will not fix the problem.

You have an Electronic control system for your AWD/4WD system. You have no vacuum lines or VSV's for your 4runner.

Why does it blink? Because the AWD/4WD Ecu is getting signals that do not correspond to the position of the Actuators.

You have 2 electronic actuators. One in the front diff which engages the passenger axle with the front diff and one in the transfer case. It engages the 4wd and further locks the center diff.


So what is wrong with your 4runner. It is permanently locked in 4wd. With out diagnosising it in person, I would suspect the transfer case actuator. It engaged into 4wd and the actuator can't reverse itself.

Take the actuator cover off the tranfer case. It will be held on with three bolts. Check the race ways inside for corrosion and see if the spindle can turn by hand.

Do not pull the gear out of the transfer case like the picture. It will be hard to put back in correctly.

If everything is clean and the spindle spins smoothly then one of your transfercase switches is bad. Easy to check- remove switch and test with multimeter. These switches look like this and there are 3 of them.

Good luck and God Speed.

 

[RfirstToy02]

We backed out of the driveway yesterday and could tell that it had popped OUT of 4WD (even though we still have flashing dash lights) - so we pulled over and popped the fuse. Temporary fix for now, at least we're out of 4WD and not hopping all over the road. We've got a mechanic that will take a look at it next weekend - will pass along all the info on this thread to him - and will come back and let you all know what he found and how we are fixed.

 

[bivey]

What did the mechanic say?

 

[Daveltang]

What to do?

So I pulled my gear out of the motor like the picture, how do I set it back in place? Is there somewhere I can get a diagram , wish I woul of seen this post before I took it apart

 

[RfirstToy02]

Well, Singtoe, you win the prize. After almost 2 years of horse-hockey, we finally got someone to spend some time with our Runner. Diagnosis: Transfer case actuator is fried. The front one will engage 4WD, and then gets stuck. Which is where we are at once again. Two years ago it miraculously disengaged, we pulled the fuse and just ran it in 2WD. Now the mechanic had to put the fuse back in to test things out, and she's stuck once again. Sigh. He tried with the cables to reverse it, and it won't. We're now looking at thousands in repairs, I'm ticked...should've just left well enough alone and ran it in 2WD.

 

[Bijan]

I just went through this. Everybody's advice so far is flat out wrong. Even the picture they have is wrong. Pushing buttons and shifting to neutral will not fix the problem.

You have an Electronic control system for your AWD/4WD system. You have no vacuum lines or VSV's for your 4runner.

Why does it blink? Because the AWD/4WD Ecu is getting signals that do not correspond to the position of the Actuators.

You have 2 electronic actuators. One in the front diff which engages the passenger axle with the front diff and one in the transfer case. It engages the 4wd and further locks the center diff.


So what is wrong with your 4runner. It is permanently locked in 4wd. With out diagnosising it in person, I would suspect the transfer case actuator. It engaged into 4wd and the actuator can't reverse itself.

Take the actuator cover off the tranfer case. It will be held on with three bolts. Check the race ways inside for corrosion and see if the spindle can turn by hand.

Do not pull the gear out of the transfer case like the picture. It will be hard to put back in correctly.

If everything is clean and the spindle spins smoothly then one of your transfercase switches is bad. Easy to check- remove switch and test with multimeter. These switches look like this and there are 3 of them.
Good luck and God Speed.

Thouht this was the issue with mine.
I have the exact same symptoms... my mechanic tested all actuators/switches/fuses... and all were good.

It is currently at the shop getting a new (used) transfer case.

 

[Singtoe]

Thouht this was the issue with mine.
I have the exact same symptoms... my mechanic tested all actuators/switches/fuses... and all were good.

It is currently at the shop getting a new (used) transfer case.

Sounds like a waste of money.

The only reason to replace the transfer case is because it is cracked or leaking or stripped out. The actuator could be bad but that is not reason enough to replace only if the the replacement TC is dirt cheap.

 

[Bijan]

Sounds like a waste of money.

The only reason to replace the transfer case is because it is cracked or leaking or stripped out. The actuator could be bad but that is not reason enough to replace only if the the replacement TC is dirt cheap.

Understandable - BUT the actuator was tested, and is currently now working on a different T-case that's been installed.

 

[UPside]

I recently encountered something similar with my 2001 so wanted to add my experience now that I've resolved it in case it helps anyone else.

My original issue was that pushing the 4wd button on the shifter resulted in the dash lights blinking (green wheels and center orange), but not stopping to show it was fully engaged (green wheels only). Like OP, I tried it a number of driving tricks, checked the fuse and disconnected the battery, but nothing worked. I removed the Transfer Case Switch (part #8422212010) to check for continuity as I've seen in other videos, and it seemed to be working fine. However, I sprayed it with a cleaner before reinstalling.

Despite folks saying there's no vacuum line on 2001-2002, there does appear to be one that goes to the Transfer Case Actuator though I didn't trace it back up to the engine bay. The end of this hose was cracking and barely attached to the Transfer Case Actuator. I cut the hose back about half an inch for a fresh end and it then fit tight to the TCA. Pictures attached of the hose running to the TCA and before/after of the hose end.

I took it for a test drive and had the same blinking problem I started with. While it was blinking, at low driving speed I pushed the dash switch and that lit up "VSC OFF" and the green wheels and orange center lights stayed on solid. When I pushed the dash switch again to turn VSC back on, it resumed with all green and orange lights blinking. With VSC on (no dash light reading "VSC OFF") and the lights blinking, I accelerated a bit more than moderately and as I slightly lifted my foot off the accelerator, the green wheel lights stayed solid and the orange center light disappeared. 4wd working once again!

I pressed the button the shifter to switch back into 2wd and repeated the process of pressing the shifter button, accelerating solidly, and as I lifted my foot it once again successfully made it into 4wd

 

[Bad Luck]

I recently encountered something similar with my 2001 so wanted to add my experience now that I've resolved it in case it helps anyone else.

My original issue was that pushing the 4wd button on the shifter resulted in the dash lights blinking (green wheels and center orange), but not stopping to show it was fully engaged (green wheels only). Like OP, I tried it a number of driving tricks, checked the fuse and disconnected the battery, but nothing worked. I removed the Transfer Case Switch (part #8422212010) to check for continuity as I've seen in other videos, and it seemed to be working fine. However, I sprayed it with a cleaner before reinstalling.

Despite folks saying there's no vacuum line on 2001-2002, there does appear to be one that goes to the Transfer Case Actuator though I didn't trace it back up to the engine bay. The end of this hose was cracking and barely attached to the Transfer Case Actuator. I cut the hose back about half an inch for a fresh end and it then fit tight to the TCA. Pictures attached of the hose running to the TCA and before/after of the hose end.

I took it for a test drive and had the same blinking problem I started with. While it was blinking, at low driving speed I pushed the dash switch and that lit up "VSC OFF" and the green wheels and orange center lights stayed on solid. When I pushed the dash switch again to turn VSC back on, it resumed with all green and orange lights blinking. With VSC on (no dash light reading "VSC OFF") and the lights blinking, I accelerated a bit more than moderately and as I slightly lifted my foot off the accelerator, the green wheel lights stayed solid and the orange center light disappeared. 4wd working once again!

I pressed the button the shifter to switch back into 2wd and repeated the process of pressing the shifter button, accelerating solidly, and as I lifted my foot it once again successfully made it into 4wd

That hose is a breather for the ADD actuator. It vents higher into the engine bay. Owners manual instructions state that if the 4wd system blinks that you should try accelerating/coasting, steering side to side, or try reverse to help the system engage/disengage.

EDIT: misread and assumed that you were at the front ADD, but regardless it’s a vent hose for the actuator.

 

[phattyduck]

That hose is a breather for the ADD actuator. It vents higher into the engine bay. Owners manual instructions state that if the 4wd system blinks that you should try accelerating/coasting, steering side to side, or try reverse to help the system engage/disengage.

He was talking about the transfer case actuator... but your comment is still true - it is just a breather line. On the transfer case, it runs up to the shifter area.

-Charlie

 

[Bad Luck]

He was talking about the transfer case actuator... but your comment is still true - it is just a breather line. On the transfer case, it runs up to the shifter area.

-Charlie

Good catch. I saw “vacuum hose” and assumed ADD actuator since 96-00 were vacuum operated. Thanks for the correction.