[Dr. Dyno]

Because it was calling for the rear differential electro-coupler to be activated. Not fully, just partially, or intermittently.

Yes that's what I observed via the LED I have attached to the electro-coupler drive signal. It would come on faintly periodically even on dry highways. The updated ECU stopped that.

 

[joebutlerjjb]

The first test is driving with the 4WD ECU unplugged. If you still get the vibration you may have a U-joint in the driveshaft that's starting to freeze up. Has happened to several members over the past year or so.

Do you need to disconnect negative battery terminal before unplugging the 4wd ecu? (2012 v6 rav4) I have the rumble strip noise between 25-40mph.

 

[Dr. Dyno]

No need to disconnect anything except the 4WD ECU. You can also plug it back in at will.

 

[joebutlerjjb]

No need to disconnect anything except the 4WD ECU. You can also plug it back in at will.

Hi Thanks, After removing the glove compartment, mine (2012V6) doesn't look like the previous pics posted. The module on the LEFT has the bigger wire harness connector on mine and there's an open slot beneath it. I just got it a month and a half ago and it only developed this issue in the last 2 weeks. The left(drivers side) front wheel has no balance weight, but the vibration isn't in the steering wheel. Its most prominent between 25-35mph and goes away over 40, but in that range it's intolerable. Brakes were recent, tranny fluid was changed at 80k (has 123k) Carfax was very good and it was the car I wanted, traded in a perfectly good 2008 CRV and I'm having doubts !

 

[Dr. Dyno]

Hi Thanks, After removing the glove compartment, mine (2012V6) doesn't look like the previous pics posted. The module on the LEFT has the bigger wire harness connector on mine and there's an open slot beneath it. I just got it a month and a half ago and it only developed this issue in the last 2 weeks.

One module is for the TPMS, the other for 4WD. If you unplug the wrong one the Tire Pressure light will come on.

 

[steveart]

I'm curious about this module. I just recently bought a 2007 Rav4 v6 and noticed the howl/whirl "engine taking off" noise and researched it to the viscous coupler. After further researching for right bearing part number, I got the bearing replaced and all is good. The noise is gone.

I heard about this ECU module upgrade for the later year models. I guess my question is, how do you guys know these used ones work? If the new module calls the electronic coupler less and reduces the noise, what if the used one does not work? How would you know its engaging the coupler when it needs to?

 

[Dr. Dyno]

If the new module calls the electronic coupler less and reduces the noise, what if the used one does not work? How would you know its engaging the coupler when it needs to?

Easy test for 4WD is accelerating full throttle from a stop on dirt or grass. If 4WD is engaging the car will take off like on pavement. If not it'll just spin the front wheels.

 

[steveart]

Easy test for 4WD is accelerating full throttle from a stop on dirt or grass. If 4WD is engaging the car will take off like on pavement. If not it'll just spin the front wheels.

Interesting. I wonder how many folks here did this to check. I've seen some of your post Dyno, I'm surprised you haven't done some electrical thing to test. I'm seeing some pretty cheap ones on ebay recently, might take a chance.

 

[Dr. Dyno]

I'm surprised you haven't done some electrical thing to test. I'm seeing some pretty cheap ones on eBay recently, might take a chance.

Of what do you speak? I do some kind of electrical design & testing regularly.

 

[steveart]

Of what do you speak? I do some kind of electrical design & testing regularly.

Did you use some clip to test the original one to see it flash when it was engaging, and were able to tell it was engaging too often? That's the only reason I would try an updated one, to wear the coupler bearing less.

 

[Dr. Dyno]

That's exactly the test I ran. And I agree likely less wear on the coupling clutches.
From my post #21 of Nov. 24, 2021:

Yes that's what I observed via the LED I have attached to the electro-coupler drive signal. It would come on faintly periodically even on dry highways. The updated ECU stopped that.

 

[KTL]

Wonder if the '09-'12 4WD ECU (89630-42040) would work as well.

 

[Dr. Dyno]

Yes that's the one I used:

Rear Differential Coupling Growl (Whine) Noise

FIX - Rear Differential Coupling Growl (Whine) Noise Hey Everyone. (2008 RAV4 Sport I4) I wanted to get a good thread with some COMPLETE information for the Rear Differential Noise that MANY of us have gone through and will go through. I just spent half my day completing this and I wanted...

www.rav4world.com

 

[steveart]

That's exactly the test I ran. And I agree likely less wear on the coupling clutches.
From my post #21 of Nov. 24, 2021:

Yeah but how do you know the new one will kick in when it needs to? I guess the dirt road trick could work but not very reliable.

Anyway, I'm just glad I was able revive an old thread. LOL, Rise 5 year old thread, rise!!!

 

[Dr. Dyno]

With my V6 the front wheels will spin quite easily on takeoff if 4WD is disabled so it must be working. Besides I have the LED connected to the coupler signal. It comes on ASA I put the car in any gear.

As for reliability how do you know your car will even start EVERY time you want it to. You don't but it does.

 

[KTL]

Bought a used 4WD ECU (89630-42040) off a 2010 and everything was plug-and-play.

 

[Sistersin]

I have the shutter on my 2007 RAV4 4wd I bought Oct 2023. Two mechanic said it needed new torq converter and transmission. Had my brother fri replace my transmission with around 182000 mikes with one with only 7800 miles and put new torque converter. He replaced a bunch of other stuff that came up on the computer reader. It still has the shutter, he replaced front bearings and axles, rear axles, had a specialty shop repair the part that connects the two drive shafts. All these things were wobbly or not seeming correct and they thought it could be making the vibrations. After the first repairs for new transmission, then the lights started lighting up on the dash. Changed a bunch of sensors new coil packs for misfires. $7000 later and the vibrations hap only when driving in d, but if you switch to 3 or give a little gas o let of gas, it stops. The lights all just came back on again last time I drove it. Code P0171 still coming up. Can all this be from the ECM, and is that the same as the one in the thread that’s in the glove box? He also changed the blendor motor and spent several hours trying to get 5he vents to work right, air only comes out the front vents. Works for a short time then doesn’t work again. This issue seems to be from glue under dash get heated and sticking where the vents change. im on disability and have now spent twice as much as I paid for the vehicle on repairs and none of my original problems are fixed. Just had new ones pop us. I’d appreciate any advice. Thanks so much.