2002 4runner no 4WD.

[BOSSIND]

Yes another one with no 4WD and flashing lights on the dash. I assume the actuator is only used in 4Hi, and moving the leave to 4LO would bypass the actuator as I manually engaged it in 4WD but LO. Still no 4WD, so I would assume this means the front diff to be the problem?


Thoughts?

 

[TheDurk]

Yes another one with no 4WD and flashing lights on the dash. I assume the actuator is only used in 4Hi, and moving the leave to 4LO would bypass the actuator as I manually engaged it in 4WD but LO. Still no 4WD, so I would assume this means the front diff to be the problem?


Thoughts?

In a 2002, there are two actuators, both electric, not vacuum like the rest of us--so a lot of what you read won't apply to you. One is on the TC and engages 4wd, i.e. the front propeller shaft for either 4Hi or 4Lo. The other is on the front diff and engages for both 4Hi and 4Lo.

The good news (for you) is the on-line FSM applies to you and not to the rest of us. I'm a 5-speed J-shift guy so I can't help much other than by looking at the manual. Look at what you get:

 

[BOSSIND]

In a 2002, there are two actuators, both electric, not vacuum like the rest of us--so a lot of what you read won't apply to you. One is on the TC and engages 4wd, i.e. the front propeller shaft for either 4Hi or 4Lo. The other is on the front diff and engages for both 4Hi and 4Lo.

The good news (for you) is the on-line FSM applies to you and not to the rest of us. I'm a 5-speed J-shift guy so I can't help much other than by looking at the manual. Look at what you get:

Thanks those PDFs are great.

So if my thinking is right by manually placing it in 4wd low, its the actuator on the from diff thats acting up, because I don't have 4wd in lo.

 

[TheDurk]

Thanks those PDFs are great.

So if my thinking is right by manually placing it in 4wd low, its the actuator on the from diff thats acting up, because I don't have 4wd in lo.

I'm sorry, I just don't really understand the specifics of your trouble description. But, if the actuator works at all, i.e. in 4H, your problem is likely in the control system. It sound as if you need to look at the 4L sending switch on the TC (D4 on the wire diagram). It's probably not telling the system that 4L is engaged and the front needs to lock up. So the front actuator never gets called.

 

[BOSSIND]

I'm sorry, I just don't really understand the specifics of your trouble description. But, if the actuator works at all, i.e. in 4H, your problem is likely in the control system. It sound as if you need to look at the 4L sending switch on the TC (D4 on the wire diagram). It's probably not telling the system that 4L is engaged and the front needs to lock up. So the front actuator never gets called.

What I'm saying is, 4L is a manual mechanical engagement of 4wd. So it doesn't matter if the actuator on the T Case is working or not, I should be driving power down the front driveshaft as a result of me manually and mechanically doing so. However the fact I still have no 4wd would be an indicator that the problem lies in the front axle or the actuator on the front axle as that one I can't manually over ride it.

 

[Grenvilleter]

However the fact I still have no 4wd would be an indicator that the problem lies in the front axle or the actuator on the front axle as that one I can't manually over ride it.

Although you have mechanical coupling to the front diff, what Dirk is saying is, your transfer case has to tell the front diff actuator it has been placed in low mode.

It does this via a switch on the xfer case itself.

If the front diff don't know the transfer case is driving it's crown and pinion, it will not apply the proper coupling to the front wheels.

BTW- Dirk...Thanks for those diagrams. They are almost exactly what I needed to put this whole system together on a logical order of operation. I've saved them to my growing "Toy" file.

 

[Brique]

If it's not going into 4wd at all and you haven't used it in a long time try this:
http://www.toyota-4runner.org/showthread.php?t=158472

It's a free fix that worked for me, if it doesn't, you're not out anything.

 

[BOSSIND]

If it's not going into 4wd at all and you haven't used it in a long time try this:
"4wd won't work" observations today - Toyota 4Runner Forum - Largest 4Runner Forum

It's a free fix that worked for me, if it doesn't, you're not out anything.

I live in Canada, I use it all the time. :smow:

 

[BOSSIND]

Although you have mechanical coupling to the front diff, what Dirk is saying is, your transfer case has to tell the front diff actuator it has been placed in low mode.

It does this via a switch on the xfer case itself.

If the front diff don't know the transfer case is driving it's crown and pinion, it will not apply the proper coupling to the front wheels.

BTW- Dirk...Thanks for those diagrams. They are almost exactly what I needed to put this whole system together on a logical order of operation. I've saved them to my growing "Toy" file.

I put it on the hoist tonight and did some testing, in 4Lo the driveshaft still turns freely along with the right tire. Do you have knowledge the T-case tells the front actuator to lock, or is that just your thinking on it? I assume when you hit the switch, the 4WD computer tell both actuators to engage at the same time. I don't know as I've only scratched the surface, I'll be tearing into it this Saturday so I'll have a much better ideal on how this system works.

Thanks.

 

[Grenvilleter]

I put it on the hoist tonight and did some testing, in 4Lo the driveshaft still turns freely along with the right tire. Do you have knowledge the T-case tells the front actuator to lock, or is that just your thinking on it? I assume when you hit the switch, the 4WD computer tell both actuators to engage at the same time. I don't know as I've only scratched the surface, I'll be tearing into it this Saturday so I'll have a much better ideal on how this system works.

Thanks.

What tire..front or rear? what driveshaft?

The transfer case switch sure affected the operation on mine but it's a '97.

As TheDurk says...your lucky the FSM manual he provided was made for your model.
Mine uses VSV's and vacuum actuators and I don't have a center locking diff so it could be completely different.

Let us know how it turns out this weekend.

 

[TheDurk]

I put it on the hoist tonight and did some testing, in 4Lo the driveshaft still turns freely along with the right tire. Do you have knowledge the T-case tells the front actuator to lock, or is that just your thinking on it? I assume when you hit the switch, the 4WD computer tell both actuators to engage at the same time. I don't know as I've only scratched the surface, I'll be tearing into it this Saturday so I'll have a much better ideal on how this system works.

Thanks.

You're wrong and he's right. T-case tells the front to lock via the 4wd ECU. Then front tells the light to go on. It's not spelled out in the stuff I posted, but the vacuum systems all worked that way, and I strongly doubt they changed that logic just because they went to an electric actuator.

 

[BOSSIND]

What tire..front or rear? what driveshaft?

The transfer case switch sure affected the operation on mine but it's a '97.

As TheDurk says...your lucky the FSM manual he provided was made for your model.
Mine uses VSV's and vacuum actuators and I don't have a center locking diff so it could be completely different.

Let us know how it turns out this weekend.

Sorry I thought it was obvious, the front driveshaft.

 

[BOSSIND]

You're wrong and he's right. T-case tells the front to lock via the 4wd ECU. Then front tells the light to go on. It's not spelled out in the stuff I posted, but the vacuum systems all worked that way, and I strongly doubt they changed that logic just because they went to an electric actuator.

I wasn't saying anyone was right or wrong, nice for you to draw the line.

From what I can tell the sensors for reporting back to the computer are on the actuator on the T case.

 

[TheDurk]

I wasn't saying anyone was right or wrong, nice for you to draw the line.

From what I can tell the sensors for reporting back to the computer are on the actuator on the T case.

Don't get your panties in a bunch. You stated an assumption. It was wrong, I corrected it. This is what we do here.

You need to carry out the procedure on page TR-52 in the second link I posted. I'm pretty sure it will fail on one or more tests.

This is the best info I have about where the switches are on the 2002. Diagram pretty much sucks and the description by No. 1, No. 2, etc, doesn't match up to the FSM or the wire diagram. Sorry, best I can do. Someone who has worked on one of these could be better able to help.

 

[BOSSIND]

Don't get your panties in a bunch. You stated an assumption. It was wrong, I corrected it. This is what we do here.

You need to carry out the procedure on page TR-52 in the second link I posted. I'm pretty sure it will fail on one or more tests.

This is the best info I have about where the switches are on the 2002. Diagram pretty much sucks and the description by No. 1, No. 2, etc, doesn't match up to the FSM or the wire diagram. Sorry, best I can do. Someone who has worked on one of these could be better able to help.

Don't be talking about my Panties till we get to know each other a little better.

Thanks, I know I have to run through the procedure and will do so Saturday, just trying to arm myself with information and rule out things or at least narrow it down to some knowns. Thanks for the part numbers.

 

[BOSSIND]

Well I had it working. Test the sensors and they are all good. The front axle is engaged but noir the T-Case. I setup to test the actuators, when I power the one on the Tcase it went into 4wheel drive. I was able to hook it back up and place it in and out of 4wheel drive right there on the hoist. Every thing was working as it should.

However as soon as I went for a drive and tested the same problem came back. So whats happening is when you hit the switch (4WD) the front axle locks, but the Tcase doesn't, once it does this you can't unlock the front axle. Thus the pulsing 4wheel drive light on the dash.

Think the actuator on the case is failing to full engage, tripping the sensors does not do anything at this point as I tried to even bypass them by jumping them.

So right now I'm driving around with the front axle locked but not the Tcase, so I guess the Tcase doesn't lock first after all.

 

[TheDurk]

Well I had it working. Test the sensors and they are all good. The front axle is engaged but noir the T-Case. I setup to test the actuators, when I power the one on the Tcase it went into 4wheel drive. I was able to hook it back up and place it in and out of 4wheel drive right there on the hoist. Every thing was working as it should.

However as soon as I went for a drive and tested the same problem came back. So whats happening is when you hit the switch (4WD) the front axle locks, but the Tcase doesn't, once it does this you can't unlock the front axle. Thus the pulsing 4wheel drive light on the dash.

Think the actuator on the case is failing to full engage, tripping the sensors does not do anything at this point as I tried to even bypass them by jumping them.

So right now I'm driving around with the front axle locked but not the Tcase, so I guess the Tcase doesn't lock first after all.

I'll admit I'm wrong if I am, but we aren't quite there yet. Did you try 4L, too, or just 4H?

 

[BOSSIND]

I'll admit I'm wrong if I am, but we aren't quite there yet. Did you try 4L, too, or just 4H?

When it was working on hoist, everything worked. After I got going on the road, it went back to what it was doing, 4L or 4H didn't make a difference. Also 4L doesn't mechanically couple the front driveshaft, just changes the gear ratio and your still dependent on the actuator to work - at least I have that confirmed now.

Any could Toyota use bolts and screws that are any softer? Frig.

 

[TheDurk]

OK, I'm sticking to my guns. I think the way it works is the 4WD ECU powers the TC actuator motor until the required one of the three limit switches shown as part of the actuator in the wire diagram gets closed. Then it calls the ADD actuator to do its thing.

In your case, the limit switch is turning off the TC actuator motor before full engagement is achieved. Thus no power to the shaft, and the detection switch, which is separate from the actuator does not engage, leaving the light on pulse. Did the light go steady when you jumped the detection switch?

In any case, I would agree that problem is in the TC/TC actuator. The actuator is sensing limit achieved before physical engagement and thus ADD engages but no power to front shaft.

 

[BOSSIND]

OK, I'm sticking to my guns. I think the way it works is the 4WD ECU powers the TC actuator motor until the required one of the three limit switches shown as part of the actuator in the wire diagram gets closed. Then it calls the ADD actuator to do its thing.

In your case, the limit switch is turning off the TC actuator motor before full engagement is achieved. Thus no power to the shaft, and the detection switch, which is separate from the actuator does not engage, leaving the light on pulse. Did the light go steady when you jumped the detection switch?

In any case, I would agree that problem is in the TC/TC actuator. The actuator is sensing limit achieved before physical engagement and thus ADD engages but no power to front shaft.

Looking at the info you gave me, the clock spring also has position indicators, so this along with the 2 sensors must play apart in getting the front to lock and unlock as I can't make it happen no mater what combination I trip on the 2 sensors. Anyways I just bought another TCase as that seemed to be the cheaper route to go. I hate to take something a part when I don't have a backup source of parts. So once that lands I'll go at it again.

Thanks for the help. No to order a bunch of seals while I'm at it.