DrivingTheAmerica

Hello Everybody,

Together with my wife, I am on a long journey from Canada to Argentina (currently in Costa Rica). We bought a 2003 4runner in the United States for the trip. I am having a problem with it. More precisely with its 4wd system. I have read a few posts since last night, including this one: https://www.yotatech.com/forums/f2/4...er-ltd-131201/ . My car symptoms appear to me to be a bit different than the ones in the post and I am not sure if I should follow the same troubleshooting approach… I am not sure how I should go about it and was wondering if someone knew that problem and/or could help me with the troubleshooting.

Symptoms:
The car transmission is automatic and I change between modes (2wd, 4wd, 4wd low) turning a round button on the dashboard. Since 3 days, when I come back from the 4wd drive mode, the 4wd light blinks for a few seconds and then disappears (as it should do and always did when disengaging 4wd). But after a moment (maybe 1-2 miles / 1 minute), the 4wd light comes back on. It is not blinking. It just comes back solid green. If I turn back the switch to 4wd drive the light starts blinking for a few second and goes solid again (like if I engaged two wheel drive normally). If I leave the switch on two wheel drive and with the light on the two VSC orange lights eventually come on (VSC OFF and VSC TRAC, if I am correct). With the switch on 4wd the VSC lights don’t come on and everything seems fine.

The low gear and rear diff lock seem to operate properly.

I came to believe that the 4wd does not disengage properly. However, if it did not disengage properly, I would expect the light to keep blinking when I turn the switch to 2wd and not to come off normally… So I am very confused about what is happening.

What I have done so far:
I mostly played around with the switch and tried to get off 4wd by going forward, reverse, and neutral… I drove around 70 miles since the problem started and tried many times to switch back to 2wd but the 4wd light always came back after a moment. When the 4wd light comes back on, I turn the switch back to 4wd to avoid turning off the VSC (i.e., avoid getting the two orange VSC light coming on).

While writing this post, I realise that I should be 100% percent sure whether the car is really in 2wd when the 4wd light is off for a moment (i.e. just after switching back to 2wd) and when the light turns back on while the switch is still set to 2wd. I will try to test this as soon as possible...

When did it happen:
It occurred after driving 3 hours on dirt roads with some nasty sections, a lot of shaking, a lot of dust, and some river crossings (one was around knee height). I drove it all in 4wd and did go into low gear at one point.

Past problems with 4wd system:
None. I have been driving the car since 6 months and more than 16000 miles. I have been switching 4wd on and off without any issue so far.

The car has 180000 miles and is 13 years old so I am thinking it might just be a blown sensor or a corrosion problem. I also do not clean the car much. So maybe some dirt / water blocked the 4wd (I thought this shouldn’t happen)?

I am actually feeling lucky to be stuck in 4wd rather than in 2wd. The 3 hours road which I took preceding the issue would not have been passable without 4wd and it was the only road to go where I wanted to go… Of course it is the Christmas break and most mechanics seem to close for a while. Moreover, my budget is limited and reading the story of people giving more than 1000$ to a dealer to fix similar issues without success scares me a bit... Being far from home, I also do not know a reputable dealer around here. Therefore, I really would like to start to understand the problem by myself (and with your help:-). I come from a country where 4x4 vehicles are not common and I am not familiar with how to fix it.

Thank you for taking the time to read this. Any suggestion on what is going wrong and how I should proceed to solve my problem would be greatly appreciated.

Merry Christmas,
Cedric

PS: this post seems to discuss the same problem but did not get much of an answer: https://www.yotatech.com/forums/f117...-stuck-292317/

DrivingTheAmerica

Hi guys,

I spent quite some time under the truck and the problem has evolved in many directions. Right now the symptoms have change to blinking 4wd and diff lock lights whenever I turn into 4wd switch and it does not stop when I push back to 2wd (actually, when it is blinking, I am stuck in 4wd with diff lock on). It does get back to 2wd when I shut the car off and restart.

I have the feeling that the ADD sensor is not doing its job.

Anybody knows how I can access/test/clean the ADD sensor on a 2003 model?

while being under the car I noticed two little hose that where disconnected: one by the ADD module, the other one by the transfer case. I thought bingo these got disconnected (and there seems to be places to connect them). Unfortunately connecting them back where it seemed to fit did not change a thing...

Anybody can tell me what these are and if they should be connected ? (I thought it is an all electric system and thus there was no vacuum lines)

Any help would be much appreciated.