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Preparing the ECM for Re-Flashing/Programming
First of all, you must locate and remove the ECM from the vehicle. It will be attached to its
place by several bolts with Torx head type. Below is an example of one of the many ECMs
you will be working with.
You will need to put the ECM flat in a table and open it by removing the four Torx bolts that
are holding together the ECM cover.
The actual device (chip) which needs to be re-flashed, will be an eight legged SMD (Surface
Mounted Device) EEPROM which is circled in red at the top-left corner on the picture above.
On other cases, the EEPROM will be located at the bottom part of the circuit board. Check
the picture below at the right for an example.
You will identify the EEPROM by the numbers on
the circuit board, which in most cases will be
“IC900” and by the numbers on the top of the
device itself, which will be any of the following
(among others):
24c02 25020
24c04 25080
93c56
93c66
95080
95040
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Below is a close-up of the chip.
You will require a capable Serial EEPROM programmer, such as the non expensive
SeeProg unit (picture below) or any other that accepts serial EEPROMS of the SPI, uWire or
I2C types. Some are expensive and some are not, but most will include protocols for
handling such type of EEPROMs. A Windows software will be included on any of those
programmers for doing the job using your personal computer.
Now you will need to READ the contents from the EEPROM device using the Programmer
and an SMD Clip (to interface the EEPROM to your programmer) and save it as a backup of
the original file and load the virgin version of the needed file into the programmer and write it
to the EEPROM.
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Ensure you place the SMD Clip in the correct orientation. Otherwise the Read/Write process
will not be possible. Once done, you just reinstall back the ECM and try ONLY in the car to
be used on, as it will be locked to it. If it is tested on any other car, it will be locked to that
other car and won’t work on the target one, needing to redo the whole process again.
NOTE: The circuit on Some ECMs will not allow to program the EEPROM on circuit. On that
case, if you do not succeed after various attempts of reflashing the EEPROM, you should
take it out (unsolder), do the process off-circuit, and then solder back the EEPROM.
Example of these vehicles, are some RAV4 ECM’s, but not all.
It is not uncommon to find that Corolla’s and Celica’s may use the same data structure for
example, so if you do not have or can not locate the needed file, you should check ALL the
files until you find one similar in structure.
Registering New Keys to a Virgin ECM
Once the ECM has been re-flashed and installed back into the vehicle, you can register your
keys (if are new) by placing the Master into the ignition, turn it until all the Instrument Cluster
lights illuminate (position 2) and count to 10. Now remove the key and repeat again for the
2nd and 3rd key. You have now all three keys programmed. If keys are used, just inserting
the Master key of the set will do the job.
Registering Additional Master Keys
(Registering additional Keys where a Master key is available)
The typical procedure for registering additional master immobilizer keys is fairly
straightforward. Carefully study the entire procedure first so you're ready to follow the
directions accurately and promptly. Begin by having new master keys cut to match the
original one.
Slide a valid existing master key into the ignition switch. Floor the gas pedal and release it
five times within 15 seconds. After you've done that, depress and release the brake pedal six
times within 20 seconds.
Now, you must remove this key and insert the unregistered master key within 10 seconds of
completing the gas-pedal/brake-pedal workout. After you insert the unregistered key, floor
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and release the gas pedal one more time within 10 seconds. Now the security light or the
word SECURITY on the instrument cluster will begin blinking. Then, the security light stops
blinking after about 60 seconds. This tells you that the new key is registered.
If you want to register another new master key, you must slide it into the ignition switch within
10 seconds of when the light stops blinking. Then promptly floor the gas pedal and release
it. Wait for the security indicator on the instrument panel to stop blinking and the second key
is registered. Usually you can register up to seven master keys.
Please remember, you cannot create a new master key from a valet or sub key, which is
gray. Watch out for a well-used valet key that the sunlight has darkened so much it almost
looks like a black master key.
