03 Toyota RAV4 ECU transmission problems / reset

[CapLeaker]

I've got here an ECU 89661-42840 from an 03 Toyota RAV4. Got the usual transmission problem that is ECU related. Symptoms are not shifting as it supposed to, no shift etc. Turn the car off, wait a minute and back on and it will work again for a bit. I think she's in limp mode here or something.

Anyway... There are tons of those RAV4 that have this problem. My problem with it is, that it's a right steering import vehicle and the dealer can't read the ECU.

I went all over the ECU resoldering a whole stack of resistors, no problem. BUT I am stuck on resetting the transmission in the ECU.

I've read up on how to delete the adaptive crap in the 25080 flash, by deleting everything on the 000100 block. My ECU has a different layout and 3 large Fujitsu IC's and a 25040 flash. The smaller flash still has the 000100 block in there, but it's almost like erasing the whole IC.

If someone can explain to me what kind of info this Atmel 25040 stores and clean the transmission adaption stuff out / verify its the same way like on the 25080 etc, would be awesome.

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Put that valve on, fixed the vacuum problem in the fuel tank and she works like a charm.

[stj]

Re: 03 Toyota RAV4 ECU transmission problems / reset

posting an un-molested 25080 dump for comparison may help
does it have a seperate computer for the gearbox like honda's?

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Unfortunately I don't have an original dump from an 25080. To your second question the answer is no. The 2001 to 2004 model years house the transmission stuff in the main ECU. The dealers used to put a new ECU in that fixed that problem. Others resoldered all the power resistors like I did, then reset the transmission in the ECU a and force it to relearn.

Since the car was imported from a different country where the steering wheel is on the right side, the local dealer can't read the ECU to reset the transmission adaption. Others took the flash off, read it, zeroed out everything in the 000100 block, put the flash back, installed the ECU, then drove around. Fixed the problem.

However, this ECU has only a 25040 Atmel flash. So it does have the 000100 block too, but I'd be erasing almost all of the flash. I did compare my dump with others from YouTube, but all the values in my dump are totally different, which makes sense. What I don't know is, if the 000100 block on a 25040 is the same as on a 25080 doing the same thing.

Don't want to really monkey around on something where I am not sure on what I am doing or erasing in this case. I did a cross post at digitalchaos, which those guys have a lot of ECU related stuff going on, but didn't get any results.

https://www.youtube.com/watch?v=TasPnQ2wPkU
https://www.youtube.com/watch?v=3QWyZrtLR4Q

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

there are scan tools that ought to do it .. think carly is one of them .

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Here is a pic of my ECU, less the Atmel 25040. That's sitting in my TL866.

I think one needs a proper scan tool, other than that you wont even get the option to reset the tranny. It's not just to read out the error codes. I never heard of carly.

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

yes a proper tool similar to what i use for v.a.g group only . its all done with measuring blocks and easy to bugger things up .
i did read about the rav 4 problems and it can lead to auto gearbox failure such as burned out clutches .

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Yep. That’s correct on the old RAV4 transmission problems. I’ve got a good scanner for Ford, but I am not sure if it does Toyota, since the software is for Fords only.

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

i use forscan for fords with elm327 .
getting delphi at some point . no idea if that would do it .

[stj]

Re: 03 Toyota RAV4 ECU transmission problems / reset

i would esr test the electrolytics.
i have complete distrust for SMD electrolytics regardless of who makes them.
i dont care if god made them and they got blessed afterwards - i still wouldnt trust any.

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

i would esr test the electrolytics.
i have complete distrust for SMD electrolytics regardless of who makes them.
i dont care if god made them and they got blessed afterwards - i still wouldnt trust any.

Me too, that why I've already done this the first thing after opening this box. Still o.k. in this regard. I knew you would say that. lol

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

For now I just did resoldered the resistors and the ground points. Put the Atmel flash untouched back on the board. Let’s see what happens.

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Well... this didn't help any at all. Same problem. Sure enough, it is a Japanese import car. The car talks in Japanese, and the stickers in the door all all Japanese too, LOL.
I took the car out for a drive and actually found out that there is no problem shifting in first, second and third or reverse / nor any hard shifts. However I had a MIL light on and didn't get fourth gear and no overdrive. I did notice a rough idle while in gear and stopped at a traffic light. Using the emergency brake and leaving the car in drive, the rough idle is gone? Weird.
Turns out I was able to read the car with an Autel scanner. The car came back with an P1653 code. I checked the gas cap and boy was there ever a vacuum in the tank! Anyway, after restarting the car, the MIL light disappeared and I had 4th gear with OD. So hopefully either fixing / replacing the gas cap and putting in an new vacuum switch will cure that bitch!

[stj]

Re: 03 Toyota RAV4 ECU transmission problems / reset

gas cap?
it's probably got a carbon filter followed by a solenoid valve and a pipe to the outside-world or the intake system.

emissions rules etc.

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Code P1653 Toyota Possible Causes Low engine oil level Faulty Oil Control Valve

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Yeah, oil control valve…. Has two vacuum hoses go to it and it’s on the left rear side of the engine. I don’t understand what the P1653 code has to do with the 4th gear being locked out? Anyway I guess they have to put that valve on and see what happens next.

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

it puts it into a sort of limp mode .
lots of cars do unexpected things when certain faults are logged such as land rover range rovers that say if the steering loses calibration because of a dead battery it will also show abs fault and disable the air suspension . same as it will if egr fault appears .

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

I never seen a limp mode that only takes 4th gear and OD away, but I go after found trouble, fix what I know is wrong and try again. See what happens... gonna be a while until I get the parts, but time will tell.

[CapLeaker]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Put that valve on, fixed the vacuum problem in the fuel tank and she works like a charm.

[petehall347]

Re: 03 Toyota RAV4 ECU transmission problems / reset

Put that valve on, fixed the vacuum problem in the fuel tank and she works like a charm.

nice one well done