4wd electrical issue
- Thread starter ScubaS
- Start date
opcorn:
ScubaS
New member
Some wild combination of luck and a perfectly worded google search has led me to hit the 4wd toyota jackpot. The attached file seems to be a toyota training course that includes the multimode system in beautiful detail. Now excuse me as a I spend the next couple of days reading each and every letter.
ScubaS
New member
It's a Christmas miracle! I have 4wd (multimode anyway).
After running low on viable options I decided to focus on freeing up the tc actuator and getting it working before worrying about any of the other issues (that I suspected might be symptoms of a stuck actuator). I had no luck freeing the actuator by tapping on it while alternating the 2-4 select. I could hear the motor try to move when I tried to jump it from the battery but it still wouldn't work properly. About a week ago I decided to bite the bullet and pull off the actuator cover (three 10mm bolted cover where the breather hose is) hoping that some bad contacts could be causing the issue or that I would at least be able to access the gear to engage 4wd by hand (nope).
Long story short: Don't pull that cover unless you're 100% sure that the problem is inside. If you do pull the cover make sure you mark exactly how the assembly is oriented because it needs to go back in the same way. I found that removing the inspection port on the top of the actuator (triangle plate with 3 8mm bolts) lets you access the gear that drives the shift fork and you can stick a properly sized torx or hex in there to break the shift fork free. You won't hurt anything because the gear connecting to the motor is on a spring to keep from jamming the motor. The actuator wasn't the problem the shift fork was.
Anyway, multimode is fully engaged right now and I'll let it stay that way for awhile to lube everything up. I know it will go back into 2wd so next up will be testing 4HL. For the record, the VSVs are working properly again. The tc is supposed to tell them when to switch and the shift fork was preventing that from happening.
**For anyone reading the symptoms in the first post and the conclusion in this post, be aware that I had multiple problems with my 4wd system that included a bad ecu so not all symptoms were related to the stuck shift fork.**
After running low on viable options I decided to focus on freeing up the tc actuator and getting it working before worrying about any of the other issues (that I suspected might be symptoms of a stuck actuator). I had no luck freeing the actuator by tapping on it while alternating the 2-4 select. I could hear the motor try to move when I tried to jump it from the battery but it still wouldn't work properly. About a week ago I decided to bite the bullet and pull off the actuator cover (three 10mm bolted cover where the breather hose is) hoping that some bad contacts could be causing the issue or that I would at least be able to access the gear to engage 4wd by hand (nope).
Long story short: Don't pull that cover unless you're 100% sure that the problem is inside. If you do pull the cover make sure you mark exactly how the assembly is oriented because it needs to go back in the same way. I found that removing the inspection port on the top of the actuator (triangle plate with 3 8mm bolts) lets you access the gear that drives the shift fork and you can stick a properly sized torx or hex in there to break the shift fork free. You won't hurt anything because the gear connecting to the motor is on a spring to keep from jamming the motor. The actuator wasn't the problem the shift fork was.
Anyway, multimode is fully engaged right now and I'll let it stay that way for awhile to lube everything up. I know it will go back into 2wd so next up will be testing 4HL. For the record, the VSVs are working properly again. The tc is supposed to tell them when to switch and the shift fork was preventing that from happening.
**For anyone reading the symptoms in the first post and the conclusion in this post, be aware that I had multiple problems with my 4wd system that included a bad ecu so not all symptoms were related to the stuck shift fork.**
I'll try to help if I can. What year is your 4Runner and is it a limited? What's your questions?
This is an incredibly detailed and helpful document. I've fixed my own transfer case troubles but I spent a long time trying to piece together the workings of the 4wd system from a bunch of different sources, and this has all that info and more in one place. Thanks for sharing!
For what it's worth, I had somewhat similar (if only because it was so puzzling) troubles with my system, and it turned out the problem was two bad sensors (one on the actuator, one on the A.D.D and a bad wire in the wiring harness that goes to the actuator. I ended up cracking it open and replacing all the wiring to the timing contacts, which fixed my problem for about $20 (My tech was talking 4 digits, which to be fair would be how much it would take to do it the right way and not my hacked together way)
My 4runner is still hesitant to shift on the fly and usually takes rocking to get in/out of H4F but it seems like exercise is the solution to that.
The one question I have is, which switch is on the TC/forward side of the actuator for any of you?The switch with the divider between plug contacts or without? The switches have been in and out both before and after I purchased the vehicle and I'm not 100% confident that the right one is in the right hole. It seems to work fine now, though.
I have a 2000 limited 4runner 4x4 I was having the flashing lights then I went upon myself to change the transfer case thinking the actuator was bad and it wasn’t the issue I changed the transfer case switches and the one on the front differential still didn’t solve the problem. Then I changed the vsv valve because the blue side (4x4) side was always giving vacuum and wouldn’t get out of 4x4 now it doesn’t pass vacuum when disconnected so that fixed that issue now it’s still only passing voltage to the blue connection it won’t switch over to the 2wd side the red side I changed the 4wd ecm still same issue so my problem is that it’s always having voltage only on 4x4 side of the vsv valve it doesn’t switch to the 2wd side can you point my in the right direction I’m so confused and tired of spending money lol
That was a lot of info there. I'm gonna need you to take some baby steps for me to understand fully what's going on.
1) You changed all 5 transfer case switches?
2) Have you verified that the transfer case actuator and ADD actuator engage?
3) What happens when you put it in 4Hi Locked?
4) If you switch the vacuum hoses for the ADD VSV does it go into 2wd?
Haha yes so much I’ve done when I switch the vacuum hose it does go into 2wd so I know the front actuator is good the rear actuator I tested it on my last tC but I recently swapped it out with a used one off another 4runner how do I test it I forgot
Yes I tested and switched all the tC switches that we’re bad
If I put the shifter into 4low it doesn’t feel different when I put it in 4 locked nothing and 2wd nothing but it always feels like it’s in 4 locked because it’s hard to turn so when I switch the hoses it feels like it’s in 2wd
If you apply power and ground to the actuator motor it should either engage or disengage depending which way you hook it up. Have you put the vehicle on jackstands and verified that it is in 4wd by spinning the tires and driveshaft?
You said there's no change between 4Hi and 4Low?
Have you checked the resistance on each of the ADD solenoids? You should have between 37-47 ohms for each solenoid.
When you put it in 2wd and switch the vacuum hoses do all the 4wd lights go out?
When I put it on jackstand all wheels spin if I change the vacuum it starts rwd only so I’m sure front add works when you say add solenoids are you talking about the switches on add or the vsv vacuum valves in the engine compartment ? And no the lights stay blinking alllll the time they never go out unless I turn the car off
ADD solenoids are the vsv vacuum valves you're referring to.
When you put it in 2wd and switch the vacuum lines have you tried pressing the 4wd button on the transfer case shift lever to see if it stops blinking? Have you tried turning the front driveshaft while you have it switched to 2wd? The front driveshaft should spin freely from the rear driveshaft.
Just to clarify, you checked 5 switches on the transfer case and the 1 switch on the front differential correct?
When you put it in 2wd and switch the vacuum lines have you tried pressing the 4wd button on the transfer case shift lever to see if it stops blinking? Have you tried turning the front driveshaft while you have it switched to 2wd? The front driveshaft should spin freely from the rear driveshaft.
Just to clarify, you checked 5 switches on the transfer case and the 1 switch on the front differential correct?
Yes the add solenoids I switch the vacuum and it runs rwd I’ll lift it and try to spin the shaft last time I had it up the front and rear would spin but the front wheels weren’t spinning I guess they weren’t locked into the diff but the shaft would spin when in drive and yes all 5 switches on tC and front diff
I have tried to press the button on the lever in and out a lot of times but same result goes back to blinking
Did you check the ADD solenoid resistance?
When you try to turn the front driveshaft while in 2wd do it with all 4 tires on the ground
Ok when I check resistance is it the solenoid or the connecting wire that goes to the solenoid ?
The solenoid with it unplugged.
