If you own a 2001, 2002 or 2003 Toyota RAV4 vehicle and you are having problems with the automatic transmission, which symptoms are harsh shifting, loss of power, launching on second or third gear and/or hard engagement when it is put in reverse, then you should know that those problems are caused by a defective engine computer, which also controls the automatic transmission.
These problems are erratic and may only show at intermittent intervals or when the vehicle is warm or have been driven for a specific time. Sometimes it happens one day and the next morning it does not show.
When the computer (ecm or ecu) is defective, it will be presenting the problems mentioned above and many of those vehicles will also show the trouble codes P0750, P0753, P0755, P0758 and/or P1760.
The defective ecm computer, stops to correctly control the transmission shifting solenoids, activating and deactivating them erratically. This must be repaired before the transmission suffer any of the common damages caused by this problem. Reprogramming or updating the computer software will NOT fix the problem. It must be REPAIRED.
If your RAV4 is presenting loss in power when launching, that is, if you stop in a red light for example and when continuing, your RAV4 moves like it is carrying a very heavy load, that is because the vehicle is staring at second or third gear instead of first gear. That, in no time, will burn the transmission clutches. Please, be aware that if the computer is not repaired and you continue using your RAV4 like this, a transmission repair bill will add to the overall cost at the end.
If the vehicle is out of warranty, most owners will do the logical thing to do, which is going to a transmission repair shop. If your transmission have not sustained any damage yet, a transmission repair attempt will not fix the problem.
Toyota issued a bulletin where it is recommending that the ecm computer be replaced by a new one, but since this have affected so many vehicles (more than 240,000 units), Toyota extended their warranty to cover this problem specifically. The new warranty covers up to 10 years or 150,000 miles, whichever comes first. This new warranty will cover both the ecm computer and the transmission. If you are having this problem and your RAV4 is less than 150,000 miles, you should first visit your local dealer before bringing your RAV4 to be repaired to any independent repair shop. The documents about this bulletin and warranty extension may be downloaded in the links below:
When the computer is send to be repaired, it should be checked, repaired and TESTED. We are highlighting on “testing” the computer, because there are several individuals, offering the repair service and while that is ok, many of them are NOT testing the computer after the “repair” is performed.
We were approached by someone that ordered the service from someone on ebay from Ohio, and after he received back his ecm, his RAV4 still had the same problems. He told us in his own words;
Needless to say about the frustration that this customer had about this. This guy was offering his “service” for a very low price, but looks like the quality of his job is as cheap as his price. We checked the computer and he damaged the computer beyond any possible repair. Whatever “job” he did was very poor and soldering was like if he was a novice. We had to replace the computer at last and his transmission problems went away immediately. Other guys from Florida are selling some “remanufactured” computers and when we checked some of them, they were all covered with a black epoxy that made the ecm to be disposable, as it would have to be thrown away in the event that the circuit area beneath that epoxy fails. Very bad practice in our opinion.
So, about testing the computer, as you may already know, most of these vehicles came with a security system called immobilizer. This system will not allow you to run your RAV4 vehicle with other than your keys, which have a security chip integrated in the black plastic handle of each key. A code for running your vehicle is programmed inside that chip on the key, as well as in the ecm computer. Both codes must match after a security algorithm is automatically run by the system as soon as you insert any of your keys in the keylock cylinder.
To actually test your ecm computer after been repaired, it must be installed in a test vehicle. In order to run the engine for the tests on the test vehicle, the ecm under test must be prepared with the test vehicle codes. Otherwise it will not run. If it does not run, no test can be done. As simple as that.
Not to mention that if the ecm is successfully programmed to do the test, it must be programmed back to the codes it had before. Otherwise, the ecm will be repaired and tested, but will not run on the owner’s RAV4, because now it has a different immobilizer code.
For a quick and quality repair, where the ecm is checked, repaired and tested you may visit the following website:
After your ecm is checked and repaired, it will be prepared with the test vehicle immobilizer code and returned to your vehicle’s code after the test is done. It is achieved by removing the owner’s immobilizer eeprom chip from the ecu circuit and installing ours for testing. After the test is done, the original eeprom is reinstalled. This means, no programming will be needed as soon as you receive your repaired ecm computer. Just plug it and you are ready to drive it.
Your ecm will be in good hands and in no time you will drive a NEW RAV4. For more information, you may visit the website above or send an email to firstname.lastname@example.org
OTHER RELATED INFORMATION
Pinout of the 2001-2003 Toyota RAV4 ECM is depicted below:
Location in the vehicle of the ecm can be seen in the next picture:
Here is a partial schematic of wiring of the solenoids on the RAV4 automatic transmission from the ecm. Note that they are all a total of 10 wires, driving 6 solenoids, 4 of them with two terminals on each one and the other two with only one terminal on each one, with the other terminal of those two coils wired directly to chassis ground.
And here is the terminal connector for those ten wires. This connector is wired to the solenoids assembly. You will see in the picture below the perspectives of each harness connector. Also, the terminals for the SL1, SL2 and S4 solenoids are shown, so electrical resistance tests can be done on their coils. The solenoids resistance in ohms is also shown in the illustration, which are the same for SL1 and SL2, 5.0 – 5.6 ohms and 11 to 15 ohms for S4. Any value out of that range means a defective solenoid. If resistance is ok, then you should proceed to test the solenoids in action by disconnecting the 10 wire terminal and applying voltage from the battery, through a 25watt bulb to the solenoids directly. If a clicking sound is not heard when energized, that is indicative of a defective solenoid too.
Below is the position of the solenoids in the assembly in front of the automatic transmission.
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