[Willrun4fun]

2008 Rav4 V6 Limited 4x4 with 92000 miles.

I tried pulling codes today with an OBDII code reader and got nothing. I need to do the paperclip option outlined but how are the pins numbered? Across then down and across again or top, bottom, top, bottom, etc..

My symptoms are it only acts up when in slushy snowy conditions. The 4x4 light will come on but not the CEL as best as I can remember. It will start surging the engine and I will see the tach jump a couple hundred rpm's at a regular interval. The headlights and dash lights will also dim at the same time.
On a very snowy morning I had it get to where the engine would not even speed up. I was just stuck there at an idle in the road for several minutes then it just started working again and the lights went out and I drove off.

EDIT: Just to clarify I should state that when it refused to move it was because the engine would not speed up at all. If it was in drive I could floor it and it would just continue to idle. Put it in park and then the engine would rev up again like normal. This past winter was very very muddy at times and I live on some crappy roads. Lots of mud got packed up under the car I had to clean out as well.

After it dries out all is OK again.

Any ideas on where to start?

 

[rav4system]

Could be the electromagnetic coupler that engages the rear wheels...maybe look to see if you can find the connector and soak it with water to see if getting wet is what's causing the issue...

 

[Willrun4fun]

Could be the electromagnetic coupler that engages the rear wheels...maybe look to see if you can find the connector and soak it with water to see if getting wet is what's causing the issue...

I edited my post above to clarify as that when it refused to move it was because the engine would not rev up at all. If it was in drive I could floor it and it would just continue to idle. Put it in park and then the engine would rev up again like normal.

This past winter was very very muddy at times and I live on some crappy roads. Lots of mud got packed up under the car I had to clean out as well.

 

[nouse4aname]

Did you try turning traction control off? It's not very useful in such situations...or at all really. In fact this almost sounds like traction control is engaging. Just to clarify it is the "4WD" warning light coming on, not the slip indicator right?

 

[Willrun4fun]

Did you try turning traction control off? It's not very useful in such situations...or at all really. In fact this almost sounds like traction control is engaging. Just to clarify it is the "4WD" warning light coming on, not the slip indicator right?

How do you turn off traction control? I have never figured out a way.

 

[Rickl]

I tried pulling codes today with an OBDII code reader and got nothing.

If neither the CEL or BRAKE lights come on there will be no codes stored. The 4x4 light is an indication the 4wd system is overheating from overuse.

My symptoms are it only acts up when in slushy snowy conditions. ....It will start surging the engine and I will see the tach jump a couple hundred rpm's at a regular interval.......
On a very snowy morning I had it get to where the engine would not even speed up. I was just stuck there at an idle in the road for several minutes th

I had the same model RAV, and this same problem occurred to me only once during the time I owned it, and it was also in deep slush over top of ice.

The answer is simple. With all 4 wheels spinning, your traction control system was constantly applying the brakes, and reducing engine output power to eliminate wheel-spin.

During the periods where the front wheels were spinning at a different speed than the rear wheels, the 4wd system was automatically engaging and disengaging the rear wheels. This caused the system to overheat and illuminate the warning light. You probably could have prevented the overheating by "locking" the 4wd using the switch. Or by not mashing the pedal so hard.

You can disengage the traction control following the instructions in this post.

 

[Dr. Dyno]

First check you battery as I mentioned on the other thread. A weak one can cause many weird issues - too many to list.

If not the battery it sounds like the rear wheel ABS (speed sensors) aren't sending a signal that the rear wheels are moving. That causes Traction Control to defeat the accelerator pedal. Still each time you press it the wheels should at least try to spin.

You will need to read the light show from the post #2 jumper.

Edit: I didn't get the impression you were continually beating on the car. If so Rickl may be right.

 

[Willrun4fun]

First check you battery as I mentioned on the other thread. A weak one can cause many weird issues - too many to list.

If not the battery it sounds like the rear wheel ABS (speed sensors) aren't sending a signal that the rear wheels are moving. That causes Traction Control to defeat the accelerator pedal. Still each time you press it the wheels should at least try to spin.

You will need to read the light show from the post #2 jumper.

Edit: I didn't get the impression you were continually beating on the car. If so Rickl may be right.

Not sure what you mean by "beating on it" Just trying to get to work in 24 miles of 3"-4" of slush and snow.

 

[nouse4aname]

In any case sounds like you could use some tires that perform better in those conditions.

 

[Dr. Dyno]

Not sure what you mean by "beating on it" Just trying to get to work in 24 miles of 3"-4" of slush and snow.

The description of your "commute" involving continuous use of the 4WD rear coupler for nearly an hour points toward Rickl being correct about overheating it especially when you throw in mud coating everything. However I couldn't find any code that would report overheating. Suggest reading the codes & going from there.

See Rickl's post #197 on the other thread. His excerpt from the owner's manual very likely explains it all.

 

[Willrun4fun]

The only light giving a code is the 4wd of 99. The others are just doing a constant flash at a regular interval.

 

[Dr. Dyno]

The only light giving a code is the 4wd of 99. The others are just doing a constant flash at a regular interval.

A constant flash sequence indicates no errors in those systems. I don't have a list of 4WD codes. Maybe someone else does.

 

[Dr. Dyno]

Found it on page TF-35. Rather than type it all here's a link:
http://share.qclt.com/%E4%B8%B0%E7%94%B0Toyota%20RAV4%20Repair%20Manual/GF1A%20Transfer/Active%20Torque%20Control%204WD%20System/0300010.pdf
Since two of the Detection Conditions are heat related, that may be the cause.