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Discussion Starter · #1 · (Edited)
If I get into mud or deep snow the 4wd light will come on in a mile or less. The 4WD light is the only one on.
When this happens the accelerator will also start to be overridden and the engine won't rev above idle. This is obviously bad as it leaves me stranded idling. Oddly enough I have found reverse still works in a pinch. Usually though if I sit and idle for a minute it will come out of it.

This is an 08, V6, AWD with 105000.

This issue I have been unable to resolve yet http://www.rav4world.com/forums/99-...008-4x4-light-comming-refusing-move-snow.html
 

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Other than your other post you linked to we had another discussion of the issue. The conclusion was the 4WD light comes on because the system is overheating and in danger of damaging itself. That's why it works again after a "rest period."
The permanent solution is use a vehicle with a more robust 4WD system. An F-250 In 4X4 LOW would do nicely.
 

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Discussion Starter · #3 ·
Other than your other post you linked to we had another discussion of the issue. The conclusion was the 4WD light comes on because the system is overheating and in danger of damaging itself. That's why it works again after a "rest period."
The permanent solution is use a vehicle with a more robust 4WD system. An F-250 In 4X4 LOW would do nicely.
Well that is a disappointing answer. So a little front wheel drive car is more capable than an AWD Rav? This is just driving down a gravel road to my house when the conditions are crappy, which is any time it rains more than .25" in the rural midwest. The other conditions in snow were on a slushy highway.

I guess I will plan on trading it off for a regular FWD sedan or hatchback this fall.
 

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You could temporally disable the rear drive by disconnecting the 4WD ECU which is mounted behind the glove box. In fact there is just one wire coming out of it that goes to the rear electro-coupler.
If I had the problem I'd put a switch in it rather than give up a 4WD vehicle for a FWD or a 4X4 one.
 

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As I said in the previous thread, this problem only happened to me once in 8 years of ownership. Although I can drive through deep snow as well as I could in my Jeep Cherokee, these unusual road conditions brought on the same symptoms that you experienced.

I believe they were caused by the side effects of traction control. I couldn't prove it at the time because I did not have the procedure for disabling traction control with me.

If this occurs on a regular basis then I suggest disabling traction control according to this procedure next time you experience the problem.
 

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^^^ What Rickl said. This is a classic case of engine bogging down when stuck, so you must disable the TRAC/VSC system:

Read the link he posted, here is the 'tap dance procedure' from the link. Seems crazy. Starting in 2009, there is a simple button you push and hold for 5 seconds, but you get to do this:

from JuneBug post:

1. Make sure the car is in Park and the parking brake is disengaged before you start the car.
2. Start the engine.
3. Engage the parking brake.
4. Fully depress the brake pedal and then release.
5. Fully depress the brake pedal and then release.
6. Disengage the parking brake.
7. Fully depress and hold down the brake pedal.
8. Engage the parking brake, then disengage it (while holding down the brake pedal).
9. Engage the parking brake, then disengage it (while holding down the brake pedal).
10. Release the brake pedal.
11. Engage the parking brake.
12. Fully depress the brake pedal and then release.
13. Fully depress the brake pedal and then release.
We've had some record snow this year, been testing the system, have switched off TRAC/VSC several times when engine bogs. Luckily, I have the magic 'button.'
 

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^^^ What Rickl said. This is a classic case of engine bogging down when stuck, so you must disable the TRAC/VSC system:

Read the link he posted, here is the 'tap dance procedure' from the link. Seems crazy. Starting in 2009, there is a simple button you push and hold for 5 seconds, but you get to do this:
when the engine bogs down because of VSC the 4WD light does not turn on.

I did have the 4wd light come on once in 10 years of owning Rav4, VSC was deactivated and I was having fun in the snow, after 2 minutes of pushing it, power was limited and party time was over...
 

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when the engine bogs down because of VSC the 4WD light does not turn on.

I did have the 4wd light come on once in 10 years of owning Rav4, VSC was deactivated and I was having fun in the snow, after 2 minutes of pushing it, power was limited and party time was over...
I haven't reached that limit I guess. Once unstuck and underway, I push the TRAC/VSC button to turn it back on. And have the option to engage the AWD LOCK button if churning below 25mph through the unplowed subdivision roads. But really, once underway, the AWD system does its thing with good traction without the LOCK button on. So temporarily disabling the TRAC/VSC nannies is the most important thing just to get moving.
 

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when the engine bogs down because of VSC the 4WD light does not turn on.
I don't recall the 4WD light coming on during my situation either, but I had pushed the 4WD Lock button when first getting into the slush.

From what I understand, there is a viscous clutch in the rear end of the RAV, and the clutch can vary the amount of torque applied to the rear end. I believe Dr. Dyno has verified this by observing the varying intensity of a light connected to the clutch control.

I would think that if the system was left in the automatic mode, the constant engaging and clutch slippage would cause the fluid to heat up and trigger the 4WD warning. Once the warning is on, the system locks out any further torque transfer until the fluid cools down.

Perhaps the OP might prevent the 4WD light from coming on by pressing the lock button, but experience has shown me that he still wont get anywhere in those conditions because of traction control.
 

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Discussion Starter · #10 ·
Just wanted to update.

Doing the two step jig on the brakes to turn of traction control helped a lot. I was able to get through the rest of the worst weather without issue as long as I did this before I headed down the bad roads.

Now the car is in the shop getting a water pump though LOL.
 

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Doing the two step jig on the brakes to turn of traction control helped a lot. I was able to get through the rest of the worst weather without issue as long as I did this before I headed down the bad roads.
As mentioned earlier, the 4WD light was coming on because the system was overheating. Most likely caused by the clutch in the rear differential constantly engaging and disengaging. Simply pressing the 4WD lock button on the dashboard will stop that problem, assuming your speed does not exceed 40 KMH , above which the lock will automatically disengage.
 
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