Hey everyone, I recently bought a Toyota 4Runner 2003 v6 SR5 and I tested out the 4WD today (silly me forgot to test it on the test drive! Big mistake!) and the green light never turned off after trying to put in in 4WD but I don’t think it ever engaged either. And when I put it to 4h and 4L the lights on the dash never came on. Only the green 4wd indicator has come on and now won’t come off. The locking differential works fine but I can’t get it to engage in 4WD at all. And just a little back story the car was serviced from a licensed Toyota dealer since it was driven off the lot according to the car fax, and it also has immaculate interior, 0 rust on frame anywhere so I definitely think it was babied and taken care of. The only thing I can think of is maybe the actuator in the transfer case may be bad? Or stuck maybe? I looked on the forum already but couldn’t find my exact problem. Thank you for your help everyone


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If the indicator is on solid it should be in 4wd. Only an issue if it's blinking or beeping.

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Not blinking or beeping, but it’s always on and is only in 2WD, and doesn’t come out if 2WD when turning to 4H or 4L. So I’m assuming there has to be a different problem no?


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What signs are there that the 4wd is not working? Usually the green on without beeps or sad noises means everything is good to go in 4hi. I find when in 4hi without center diff (CDL) locked, you can feel a significant pull from the front in turns. I find that I feel the pull the most when going around roundabouts. This is an simple check to see if its working. 4hi is okay to use on the street as long as the CDL is not locked, since the center diff is there to alleviate binding.

If in 4wd, the front diff was not engaged and CDL was not locked, then you would not be able to move. All power would be sent to the driveshaft with the least resistance, which would be the non connected front. I think since the green light is on and you're able to move with CDL both lock and unlocked, then 4hi must be okay.

With the v6, you have 4 drive functions

1. 2wd - No lights on, rwd
2. 4hi - Can engage while driving up to 50 or 60mph, it will beep if you try while going faster. Green drive train shaped light next to R on dash, front diff is enguaged, CDL unlocked by default but can be locked.
3. 4lo - Must be completely stopped and in neutral, foot may need to be on the brake. Orange "4 LO" light appears above the PRNDL on the dash, CDL unlocked unless you've already locked it from 4hi. ATRAC will work in 4lo if you have slipping while driving under a certain speed.
4. Center Diff Lock - Can lock when in either 4hi or 4lo while moving. Orange drive train shaped light with x on tcase located next to the P on the dash. VSC off light will also come on next to the 32L on the dash

Since you'rte having trouble with lights not turning on or off, could you go through each of the options and note which lights are turning off or staying lit?

4lo is what commonly gets stuck if not actuated a few times every month. If this is your problem, there are a few threads on getting them unstuck using various methods without removing.

Well with my problem ALL lights besides this green light, and locking differential light do not turn on no matter what I do. If I put it in 4hi, at a roll and at least try to cut the wheel all the the way going slow. There is no drag or “crawl” you’d commonly feel in a 4wd vehicle. So I believe the 4wd is not engaging at all but the car thinks it is still in 4wd. From what I am experiencing that is the best way to explain it

Gotcha, I was thinking the CDL was able to be engaged and disengaged in 4wd. As you mentioned, sounds like the issue is tcase related. If the issue was front ADD, then it would go into 4wd and not move unless CDL was unlocked.

I'm not really an expert on the 4wd electrical stuff, but some troubleshooting stuff I've read in the past:

• Possibly try and swap the 4wd ecu with another one from a buddy or local toyota group friend. I believe its underneath/behind the glove box. If the issue persists then its something in the tcase, if not, the your 4wd ecu is having a rough time.
  
• check the tcase actuator breather hose. If its not attached or dry rotted, then some crap, debris, water, etc could have gotten in there and screwed some stuff.

I don’t think I have anyone around honestly to do that but I can easily put it on the lift in my garage, and take apart the actuator on the T Case and inspect to see if there’s any Crap in it. First I’ll try tapping on the transfer case while it’s set to 2H and hopefully it disengages the green 4wd light. But I still don’t see the physical 4h light on the dash so I’m really not sure if it’s in 2 or 4...


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Nice that you have a lift to get it up there, that will be a big help over setting in on jackstands lol.

I don't think theres a 4hi light like the 4lo light that spells it out, just the green drivetrain light

That is correct, there is no "4 HI" light. Under normal operation, when you switch the dial to 4H, the green drivetrain light should come on and stay solid green. From what you've described, it does sound like the actuator was not regularly used which would explain why neither 4H or 4L is engaging. However, that doesn't explain the 4H light coming on and staying on; that seems like a potential problem with your engine control module.

You can’t lock the center dif if it’s in 2WD. Just to be clear, if you move your switch back to 2WD, the green light doesn’t blink at all or extinguish?

No it doesn’t, if I click the front differential button it will lock it no problem. So I’m assuming it THINKS it’s still in 4wd.. I’m gonna put it on the lift and let it idle in drive just confirm that it is or isn’t in 4wd but I definitely don’t think it is


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Is it possible checking any codes will pop up with no check engine light?


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It's probably stuck in 4hi. This vehicle can easily be driven on the highway and turn/back up with no drag. Only feel the typical groaning/crawl in 4lo. Again there is no 4hi light, only 4lo.

Put that bad boy on the lift and throw it in drive. You'll see for sure if it's on 4hi or not lol.

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If my 4R 4WD system was going to be permanently stuck in any one mode... 4WD with the center TC unlocked would be my pick.

You can still drive it on and off-road without any noteworthy negative effects.

Wish I would have read these before hand! Well I made a small mistake and hopefully didn’t fry the ECU.... I took off the + control instead of the - to see if maybe a simple reset would help if it was a computer problem. Well I connected the + back after 15 min, started the truck and the 4wd light was on and also the maintenance light came on and starts to flash upon start up. Then goes away for the 1st 4 start ups, then the last one that went away and the ABS was blinking.. last start up no bad lights were on and looks to be back to normal, hopefully didn’t fry anything and I’ll be able to put on lift tomorrow and get back to you guys about the 4wd... hope for the best I guess lol


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