gmcmanus663
Member
Whenever I get in the truck the 4wd lights are blinking. Regardless of the 4wd position switch on the t-case lever. Whenever I press it nothing happens. I doesn't even seem like anything is attempting to engage
2002 4wd won't engage
- Thread starter gmcmanus663
- Start date
Whenever I get in the truck the 4wd lights are blinking. Regardless of the 4wd position switch on the t-case lever. Whenever I press it nothing happens. I doesn't even seem like anything is attempting to engage
gmcmanus663
Member
I have a question about when you put the t-case in neutral and you make sure all of the lights are off on the dash. My 4wd lights have been blinking constantly since the problem first came about. Regardless of whether I turn the truck off and back on, they always come on when the key in on truck running or not. I'm not sure if anyone knows if this means anything other than the system knows it hasn't engaged in the standard time (3 seconds I think)
Plastics guy
New member
It sounds like you need to check your front Actuator. There is a way to bypass the wire harness to check the actuator motor to test with 12v power.
If the motor works. It's most likely one of the electric switches on the tcase
If it doesn't move:
If you hear noise but no movement pull the actuator out of the front housing and then use a screw driver to free up the ring that slides right to left to engage the passenger side axle. It's common for them to gum up without use.
Last ditch effort would be to manually disengage the front axle by removing the front actuator, there is a groove on the ring that a fork coming off the actuator slides into. This allows for the ring to be moved right and left to engage 4wd. If you manually slide the ring so 4wd is disengaged then reinstall the actuator with the fork out of the groove. The fork should now sit on the outside of the ring/groove as to simply keep it from shifting on its own. It's a bandaid fix but at least should get you out of 4wd.
If the motor works. It's most likely one of the electric switches on the tcase
If it doesn't move:
If you hear noise but no movement pull the actuator out of the front housing and then use a screw driver to free up the ring that slides right to left to engage the passenger side axle. It's common for them to gum up without use.
Last ditch effort would be to manually disengage the front axle by removing the front actuator, there is a groove on the ring that a fork coming off the actuator slides into. This allows for the ring to be moved right and left to engage 4wd. If you manually slide the ring so 4wd is disengaged then reinstall the actuator with the fork out of the groove. The fork should now sit on the outside of the ring/groove as to simply keep it from shifting on its own. It's a bandaid fix but at least should get you out of 4wd.
FlipStyle54
New member
I'm guessing its the front actuator. I may be in the Baltimore area later this week if you want to a get a second opinion on it? I'm maybe coming down from Wilmington.
Supermoney
New member
Ok, 1, read through my threads, I went through the same issue.
1: replace all 4 switches. the 2 on the top are a ***** to get to, but you have to do it
2: if that doesn't work, its your front actuator, test with 12v and test the rear one too but 90% of the time on the 01-02s its the front actuator
fluids, and keep trying to engage won't do anything, good luck
1: replace all 4 switches. the 2 on the top are a ***** to get to, but you have to do it
2: if that doesn't work, its your front actuator, test with 12v and test the rear one too but 90% of the time on the 01-02s its the front actuator
fluids, and keep trying to engage won't do anything, good luck
phillyd162
New member
Which switches?
My 4wd saga. 2001 Sport with 245k. Original owner told me 4wd didn't engage due to the charcoal canister issue...I never bothered to try it. Ran perfect in 2wd, no issues.
Bumped the 4wd button back in June, and since then, blinking lights and random grinding, stuck in 4wd. So far friend doing work for me on it has done:
1) Front actuator switch, replaced
2) Rear actuator switch, replaced (both of these the common ones listed, from Toyota OEM)
No change. More than one fluid change, it was gunky, and now clear. Still blinking. Just not grinding as much. Disconnected & pulled fuse this week, lights stopped blinking and it seemed to go into gear easier, back & forward. Thought he finally got it, then took for a test drive and back to blinking and still stuck in 4wd.
Still lost, piece by piece, and it's not coming out. Bigger actuator issue, switches or?
gmcmanus663
Member
I'd appreciate that very much, but the truck is with me in Daytona Beach florida where I am going to college. I'm gonna try and test the front actuator tonight or tomorrow
gmcmanus663
Member
So tonight or tomorrow I'm going to try and test the front actuator. Quick question: how can I tell if the front diff is engaged or not. Obviously either the transfer case or the front diff are engaged because when in gear and moving the driveshaft moves as well.
I'm guessing jacking the truck up and spinning a front wheel would tell me if the diff is engaged if the driveshaft spins. Just a thought
Also what do you mean by bypassing the wiring harness to check the front actuator.
And as far as the two switched on top of the t-case. I bought one (non oem.. just to check, it was cheap enough to try without breaking the bank). One thing I noticed was that it only "fit" with one of the wiring harnesses. The plugs are different. Do you have a part # for both?
Thanks again for any help
gmcmanus663
Member
All 4 switches? I know of two on the t-case. I've seen pictures of one on the front diff but the later (at least 02s) do not have one there.
I've changed fluids and they weren't bad to begin with. I'm leaning toward the actuator at this point. Hoping its something more simple and less expensive but if it is so be it. I just want to figure out the issue at this point regardless of cost
gmcmanus663
Member
UPDATE:
I was able to get under the truck and do some snooping and testing. First things first, the actuator.
I tested the front actuator using this thread from yotatech. There is a pdf. of a page in the FSM that shows what to do.
- I checked the continuity. Test 3(b) showed 2.5 ohms. That's in the range so we're good there
- Test 3(c) I got absolutely no reading. I want to try it again because I think maybe my ground for the test wasn't good enough. Is it normal to just get no reading? Even if the part is bad?
- Test 4 I applied 12v to the actuator motor. First (+) to terminal 2 and (-) to terminal 6 and then vice versa. I got nothing each time.
Just as the person in the other thread, I am thinking the issue if the front actuator. Before I drop over $300 on this part (from here: https://www.1sttoyotaparts.com/oempartscat.html) I want to be absolutely sure that its the right thing. It was mentioned earlier in this thread about 4 switches. I believe I have located them all. The two on top of the transfer case that are harder to get to look different than the two right behind the t-case actuator. I just want to make sure that the ones I was looking are the same as the switches mentioned earlier.
Speaking of said switches does anyone know how to test them to see if they're good?
Sorry for the long post. Any help is greatly appreciated. I'm going to call the dealership that the site I linked gets the parts from and see what the return policy is and if it's reasonable I may bite the bullet and just buy the actuator and test it while plugged into the truck before bolting it up to make sure.
Thanks again,
Grayson
I was able to get under the truck and do some snooping and testing. First things first, the actuator.
I tested the front actuator using this thread from yotatech. There is a pdf. of a page in the FSM that shows what to do.
- I checked the continuity. Test 3(b) showed 2.5 ohms. That's in the range so we're good there
- Test 3(c) I got absolutely no reading. I want to try it again because I think maybe my ground for the test wasn't good enough. Is it normal to just get no reading? Even if the part is bad?
- Test 4 I applied 12v to the actuator motor. First (+) to terminal 2 and (-) to terminal 6 and then vice versa. I got nothing each time.
Just as the person in the other thread, I am thinking the issue if the front actuator. Before I drop over $300 on this part (from here: https://www.1sttoyotaparts.com/oempartscat.html) I want to be absolutely sure that its the right thing. It was mentioned earlier in this thread about 4 switches. I believe I have located them all. The two on top of the transfer case that are harder to get to look different than the two right behind the t-case actuator. I just want to make sure that the ones I was looking are the same as the switches mentioned earlier.
Speaking of said switches does anyone know how to test them to see if they're good?
Sorry for the long post. Any help is greatly appreciated. I'm going to call the dealership that the site I linked gets the parts from and see what the return policy is and if it's reasonable I may bite the bullet and just buy the actuator and test it while plugged into the truck before bolting it up to make sure.
Thanks again,
Grayson
Here are a couple of threads that will help. There are good photos and good information to help diagnose the issue.
gmcmanus663
Member
Well, this problem was finally put to rest a few weeks ago after months being down at school and not having any time or place to do the job. I came home for spring break and my brother and I put a brand new oem front diff actuator in. Lo and behold we've got 4wd!
Unfortunately I didn't get any pictures during the install. My brother is a tech at Lexus, so I was able to bring my rig in to their shop after hours to do the job. We were also able to do the job without dropping the front diff like many others suggested. I can go more in detail about how we did this and take pictures too if anyone is interested.
I'm just happy that I've got 4wd again. It came at a price but I figured oem (with my brothers discount) for $288 shipped was worth it. Too many horror stories about aftermarket actuators failing so soon.
Again if anyone is interested in how we got the actuator out I can go into more detail or even make a dedicated thread about this, just let me know.
Unfortunately I didn't get any pictures during the install. My brother is a tech at Lexus, so I was able to bring my rig in to their shop after hours to do the job. We were also able to do the job without dropping the front diff like many others suggested. I can go more in detail about how we did this and take pictures too if anyone is interested.
I'm just happy that I've got 4wd again. It came at a price but I figured oem (with my brothers discount) for $288 shipped was worth it. Too many horror stories about aftermarket actuators failing so soon.
Again if anyone is interested in how we got the actuator out I can go into more detail or even make a dedicated thread about this, just let me know.
SIN-Japan
New member
Please do!
gmcmanus663
Member
Will do, once I get some time I'll get some good pictures and make a thread on it. Once I do that I'll link it here for sure
This is exactly whats happening to my 02 Limited. Flashing lights, front driveshaft turning on D but front tires not spinning. I'm waiting on a new oem actuator so I hope that fixes my 4WD like it did with yours.
Thebeastlives
New member
Yea these Toyotas can have the 4wd system fail from lack of use, corrosion or the lack of maintenance on the diffs or transfer case. Lose it or use it is 1 of keys to avoiding your 4wd system to fail and having to spending tons of money to fix it.
gmcmanus663
Member
Couldn't agree more. In the manual it even says to engage the system for about 10 miles a month at a minimum.
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