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2008 RAV4 Limited V6
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Probably not. All the repair shops on ebay show 01-03, I guess Toyota probably changed the design by 04.
They also changed to an entirely different engine.
 

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Great Thread!

I resoldered my ECU only to get other symptoms like 2 sec lag before engaging reverse and slow engaging and slipping before engaging 3rd gear.
Took the car to the Toyota dealer and asked them to flash my ECU. First they told me that the transmission was beyond repair. I looked at them and told them their wrong and insisted that they should flash the ECU. Well they didn't know how, so I gave them Toyota Technical Bulletin (US) and they gave it a try.
Voila....the transmission is healthy again. (I hate to use workshops)
Still have some whining in first and second gear(will check the grounding to see if I can get rid of it) but it shifts like new.
So thanks you for this thread!!
Regards from Norway.
 

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Auto Trans question.
.
2002 Rav4 Auto, 2WD (if it matters BLACK) 180,000 miles.
All prev. owners took care of it.
.
Temp. 18*F, parked overnight and started normally.
I started the Mrs. Rav4, without more than 15 seconds warmup I put it in Drive.
I noticed it seemed to hesitate then drop into gear. Timing, about 1/2 second each.
Once it warmed up, no issue.

Said hesitation was more like a SOFT SHIFT then NORMAL SHIFT. I have no idea if the trans slips, I didn't drive it.

I don't drive it so I'm asking, is this normal or could this be the ECU needs re-soldering???

THANKS
 

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This is how I fixed it:

My Rav4 had the classic issue with the gearbox. Banging into reverse, slipping between 1 and 2 andd then banging 2nd into place. High fuel consumption.

I identified the problem, the ECU needed resoldering of the resistors.
I took the unit away, opened it and added a tiny amount of solder on all the bigger compontents on both sides of the board. Power resistors, surface mount resistors, capacitors, diodes and transistors. I even resoldered the big connector. Be careful when you solder so you dont overheat the components, especially the diodes and transistors. Be quick on every solder joint and dont put too much new solder. You can also use only flux and reheat the soldering joint, but I had no flux so I needed to solder a little bit with flux containing solder. I used lead free solder and it worked fine. Use a cheap small tip soldering iron used for electronic components and clean the tip using a sponge between every few solderings.


This took away the initial problems, but now instead the gearbox slipped between 2nd and 3rd gear before banging it into place. I researched more and found out that the ECU has a self-learning function to know when to change the gear. The ECU have been learning how to shift with broken solder joints on the small resistors that is involved with shifting. After you solder the joints to the small surface mount resistors, the ECU:s self-learned memory needs to be cleared. Toyota can do this if you clearly describe the problem and they understand it, but it is way cheaper and easier to do it yourself.



I ordered a MINI-VCI cable for around 20-25 USD from Ebay that came with a small CD with the Toyota Techstream diagnosis application. I installed the applicationon my old Windows XP laptop, as it is made for older operating systems. I did not try on my newer laptop, but maybe it works if you can use the "run on Windows XP" in the right-click preferences menu.


I connected the cable to the computer and OBD socket, chose the right car and model. Select the ECU in the list (engine ECU) and press the green arrow. Wait until it loads and press Utilities (or similar). There you can choose to erase the memory for the self learning function.


Efter this I started the car and now it shifts like a dream again. Thanks everybody on this forum.
 

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my experience with the ECU going into self learning mode - just yank the battery cable for 15 minutes. You'll notice the engine acts funny for a while as it's re-learning everything. Don't think it needs to be 15 minutes.
 

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Do you have some before and after pictures of some solder joints to see what a bad one looks like?

This is how I fixed it:

My Rav4 had the classic issue with the gearbox. Banging into reverse, slipping between 1 and 2 andd then banging 2nd into place. High fuel consumption.

I identified the problem, the ECU needed resoldering of the resistors.
I took the unit away, opened it and added a tiny amount of solder on all the bigger compontents on both sides of the board. Power resistors, surface mount resistors, capacitors, diodes and transistors. I even resoldered the big connector. Be careful when you solder so you dont overheat the components, especially the diodes and transistors. Be quick on every solder joint and dont put too much new solder. You can also use only flux and reheat the soldering joint, but I had no flux so I needed to solder a little bit with flux containing solder. I used lead free solder and it worked fine. Use a cheap small tip soldering iron used for electronic components and clean the tip using a sponge between every few solderings.


This took away the initial problems, but now instead the gearbox slipped between 2nd and 3rd gear before banging it into place. I researched more and found out that the ECU has a self-learning function to know when to change the gear. The ECU have been learning how to shift with broken solder joints on the small resistors that is involved with shifting. After you solder the joints to the small surface mount resistors, the ECU:s self-learned memory needs to be cleared. Toyota can do this if you clearly describe the problem and they understand it, but it is way cheaper and easier to do it yourself.



I ordered a MINI-VCI cable for around 20-25 USD from Ebay that came with a small CD with the Toyota Techstream diagnosis application. I installed the applicationon my old Windows XP laptop, as it is made for older operating systems. I did not try on my newer laptop, but maybe it works if you can use the "run on Windows XP" in the right-click preferences menu.


I connected the cable to the computer and OBD socket, chose the right car and model. Select the ECU in the list (engine ECU) and press the green arrow. Wait until it loads and press Utilities (or similar). There you can choose to erase the memory for the self learning function.


Efter this I started the car and now it shifts like a dream again. Thanks everybody on this forum.
 

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Just thought I'd share my ECU success story. My 2002 Rav started the hard shift from 1/2 and the neutral drop from 2/3. I tried the soldering and reinstalled. Still doing it. I then went to Digikey and for about $9 I ordered all of the electrolytic capacitors that are on the board (there's 3 different ones, 47uf, 220uf, some 50v, some 10v.) I tested the capacitors on a leak detector I have. Two were for sure bad. I replaced them all, reinstalled. I DO not own the OBD2 cable or any software= SO, I removed the negative battery cable and left the headlight switch on overnight to drain any left over stray current. I then took the car out and at about 70 miles, the computer relearned and the car now drives like new. SO, it's not only those resistors that could be causing you issues. AND I repaired it myself for less than $10!!
 

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Well in case you didn't see my little post in that 20 page thread, I have a video posted which describes how to fix your rav4 ecu yourself. It takes about fifteen minutes and all you need to do is re-solder some resistors. I have verified that this is the problem, and that this is the proper fix to it. In the video description there are links to two still pics which highlight the resistors that need soldering.


Please leave comments about your successful repair so that others will know that the fix is genuine. Thanks-Jake



  • I know how to solder, but I won't risk my ride by trying to fix my ECU. Heck, I paid 250. To get mine rebuilt with all new resistors and all solder joints redone with a warranty. Look at it this way, professional ECU shops do 100s of these a week and your going to hope you get it right the first time through? Not logical. And you have to use lead solder, hmmm i a little lead poisoning cant be bad right? 250. Is money well spent for me. ALL 2001-2005 ECUs have cheap defective Fujistu solder. So does a whole range of Fujistu PCs and medical gear. It will micro fracture/crack over time depending on the mileage and heat in your area.and then the resistors get old and fail.
 

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Hi, I soldered my ECU myself and it did solve some shifting issues but created a new issue. Maybe you can help?
Since I "repaired" the ecu I think It somehow triggered my torque converter to stop functioning properly. After doing the ecu soldering the car seem to start shuddering at 40 mph + when maintaining speed. It feels like I'm driving over small bumps in the road, but I'm not. Also, when I turn the overdrive off it this shudder does not happen. Also, it almost seems like the gas gauge is dropping rapidly. Like i’m getting like 10 miles per gallon all the sudden?!?! This was not happening before I messed with the ECU!! Wondering If I can go back to the ECU a figure out what I need to un do? Geeze I feel a little silly saying all this!

Thank you!
 

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About the 15min without power. Wouldn't the ECU drain when you remove it from the car or is the transmission memory located elsewhere?
 
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