I have a 2001 rav4 with a check engine light that won't stay off.
A few months back I researched this same issue on this subject, and found a plethera of information, including information about a factory recall to have the CPU unit of the car reset to fix the problem, which I did. Of course the light came back on shortly afterwards.
To give a little more info, I have have the O2 sensors check, and the are OK. The car runs great, and just recently passed the emission test for the state inspection (done by the dealer)
The same dealer is now trying to tell me that it's my Cat. converter that needs to be replaced, but of course won't guarantee that the light won't come back on.
I remember reading similar problems on this forum of people replacing the Cat. converter and it not fixing the problem, but can't find any info on it now.
I have a problem beleiving that the Cat. is the problem here, since it has always passed the emission test, does not produce any odor or have any rattles. I believe that the CPU needs to be properly fixed or replaced, but need some info on the subject.
Can anyone help?

I had this same problem with my Mazda Pickup a few years ago. The check engine light came on when it was time to change the Oxygen Sensor. When it was changed out, the light stayed on. A mechanic friend told me that the computer needed to be reset as well. He knew how to reset the computer, and all was right with the world after that. I dont know if the Rav is that way or not, but it would be something to look into before changing the Cat converter.

I bought a 2001 Rav4L brand new and the check engine light came on in 2002. When I took it to the dealer, they told me all kinds of stories about the Catalytic, the sensors, BLAHBLAHBLAH. I didnt believe any of it for a minute. I finally just received in the mail a month ago (yah 5 years with that dam light on!) the Toyota ECM upgrade free card. Since the trans was starting to act up, shifting hard, slipping, jerking, etc, I mad an appointment and took it in. I asked them to check the trans while they were pinging the ECM, and sure enough, it was messed up. Since there is 100k on this car now, I had already pulled the tranny pan to see how bad it was. Then I took it to the dealer. The dealer told me they were pretty sure it was the transmission computer, so $708.00 later, it works better than ever. With the ECM upgrade for fuel and emissions, and the new computer for the trans, we now have more power, we get 26.5 MPG,(never got better than 23 before) and the trans shifts smooth as silk, better than when I bought it brand new.
The dealer did me right in my opinion and even though the trans computer was a large hit, it was way cheaper than a 4g replacement trans that doesnt include a trans computer!
Good Luck!

Bill

Thanks for the info.
Did the CPU upgrade you had done have any reference numbers associated with it? I what to check if it's the same CPU reset that the dealer has supposedly already done.

Rich

Rich,
On the front of the envelope that I received from Toyota, the number is SSC#601. Hope this helps and good luck!

THIS IS THE FIRST TIME I BECOME A MEMBER OF A FORUM, I AM SEARCHING FOR SOME ANSWERS AND SUGGESTIONS. PLEASE HELP! I BOUGHT MY TOYOTA RAV4 BACK IN DEC. 2000. I HADN'T HAD ANY MAJOR ISSUES WITH MY CAR UNTIL MARCH 2008. I RECEIVED THE ECM RECALL BULLETIN FROM THE DMV BEFORE I REGISTERED IT DEC 2007, SO I TOOK IT TO A TOYOTA DEALERSHIP FOR SERVICE. NOW, I CAN'T REMEMBER IF THE RECALL WAS TO REPLACE OR REPROGRAM THE ECM, DO YOU KNOW?

EVERYTHING I'VE READ ON THE FORUM ABT RAV IS ALSO HAPPENING TO MINE; SHIFTING HARD, JERKING, SLIPPING, BINDING, HESITATING, ETC. I TOOK IT TO A LOCAL MECHANIC AND I WAS REFERRED TO A TRANSMISSION EXPERT. THE DIAGNOSTIC INDICATED THAT A SHIFT SOLENOID (SL2) NEEDED TO BE REPLACED AND UPON PULLING THE PAN FROM THE TRANNY ONLY A SMALL AMOUNT OF PARTICLES WAS NOTED, SO IT WAS DRAINED AND FLUIDS WERE REPLACED. I WAS ADVISED OF MY OPTIONS OF INSTALLING A NEW TRANSMISSION OR REBUILDING THE EXISTING. BOTH OPTIONS WERE TERRIBLY EXPENSIVE $2457-$3057.40+, SO MY FATHER SUGGESTED I GET A SECOND OPINION,.

HE TOOK IT TO ANOTHER MECHANIC WHO REFERRED HIM TO A 2ND TRANSMISSION EXPERT. THERE THEY REPLACED THE SL2 FOR $408, WE TOOK IT HOME AND THE PROBLEM SEEMED TO HAVE GOTTEN WORSE. WE TOOK IT BACK AND WAS ADVISED THE TRANSMISSION NEEDED TO BE REPLACED AS WELL, AND THAT THE SOLENOIDS WERE HEATING UP AND BURNING OUT BECAUSE OF THE BAD TRANSMISSION. THEY KEPT MY CAR FOR OVER A WEEK AND THESE REPAIRS COST $2397. ALL SOLENOIDS WERE REPLACED,OVERHAUL KIT, TORQUE CONVERTER REBUILT, 10QUARTS OF TRANSMISSION FLUID ADDED( I DIDN'T KNOW IT TOOK SO MUCH, I THOUGHT IT WAS MORE LIKE 4-5 QUARTS). I PICKED IT FOR THE 3RD TIME AND MY CAR WAS STILL NOT OK!

WHEN I WENT BACK THE ORDER WRITTER INDICATED THAT THEY TEST DROVE IT AND FOUND NOTHING WRONG WITH IT. IF THAT WERE THE CASE, WHY WAS THE ENGINE LIGHT TURNING ON AGAIN AND THE CAR WAS STILL HARSHLY SHIFTING?! THEY AGAIN REPLACED ONE OF THE NEW SOLENOID INDICATING THAT IT WAS A DEFECTIVE TOYOTA PART, BUT THAT STILL DIDN'T CORRECT THE TROUBLE. I JUST TOOK IT BACK AGAIN THIS WEEK AND I GOT A CALL THAT THE ECM NEEDED TO BE REPLACED FOR $1100, HE MADE REFERENCE TO THE BULLETIN THAT WAS PUT OUT BY TOYOTA. HE INDICATED THAT NOT REPLACING THE ECM WOULD CONTINUE TO RUIN THE TRANNY. DOES THAT MAKE SENSE?? I DON'T KNOW WHAT TO DO?

NOW I FEEL THAT ALL THE OTHER REPAIRS WERE NOT NECESSARY, BUT HOW WOULD I KNOW. DOES THE ECM CAUSE THE TRANNY TO GO BAD?

DO YOU THINK THAT THE TRANSMISSION COMPUTER IS WHAT IS DEFECTIVE?

THANX![font=Arial][size=6]

It's a good possability. I've seen one a while ago, toyota say's there is a problem with the main boards when they get hot which causes the trans to go bad