2001-2002 Chrysler Sebring and Stratus ECM Immobilizer Bypass

We have been asked many times about turning off the immobilizer of the 2001-2002 Chrysler Sebring and Stratus 2.4L car, with any of the following ECMs:

If you are going to replace the ECM with a used or recycled ECM, it is easier to just get it programmed with your VIN number, but for those who somehow are “tired” of the immobilizer failing and want to venture in doing this by yourself, of course, without the necessary scanner to program it and enter the VIN number, here are some instructions.

Know that you will need an (1) EEPROM programmer for doing it (a cheap one can do it), also a (2) heat gun for desoldering the chip, (3) desoldering copper braid for cleaning the solder out of the circuit board, and a (4) SOIC-8 adapter to connect the SMD chip to the programmer. Needless to say, this is a technical job but the equipment needed for this method costs less than what it would cost to buy the special equipment and online services to program the ECM through the diagnostic port. However, this is more expensive than bringing it to a professional to do the job. About the chip, it does not matter what number the chip has printed on it, you may read and write it as a 95040 type EEPROM.

The internals of the ECM is normally submerged in some red silicon goo for moisture and/or water protection. You will need to “dive” into it and cut the silicon so you can reach the EEPROM chip, unsolder it, program it using the instructions here and then solder it back in the circuit.

Not discouraged yet??? Ok, go on then.

First, you will need to open the ECM and find the location of the EEPROM chip, and CAREFULLY start cutting the silicon to uncover the chip. It is identified as “Z12” in the circuit.

Make sure you remove all the silicon around the chip without harming the chip, neither the circuit around it. Then, before removing the chip, take note of where pin #1 of the chip must be facing when installed back. If you put it in backward when reinstalling it, the engine won’t start.

Now with a heat gun, set to blow around 380 degrees F, carefully remove the chip and clean the solder pads with the desoldering braid product like the Chemtronics brand (the best).

Make sure that the leads of the chip are free from silicon and are clean to avoid read/write errors. Now put the chip in a SOIC adapter and connect it to your programmer. The adapter could be a SOIC-8 clip, or a SOIC-8 socket, or any other means you can find to ensure connection to the programmer.

These EEPROMs are cheap (could be as low as $1 each), so as an alternative, you may order a blank 95040 chip from eBay or any other marketplace and program it with your car’s VIN as instructed here so you just swap chips as soon as you take the old chip out and clean the circuit, skipping the part of cleaning and removing all the silicon and other materials from the old chip.

To read/write the chip, choose in your programmer the 95xxx EEPROM family and select the 95040 chip, which is a 512 bytes chip. It can help to choose the brand of the chip (ex: ST, Texas Instruments, etc.), but generally, any of the available brands will do as most of these chips use the same programming algorithm. At the moment of writing, just write the file and re-read it twice to see if the same checksum prevails. If not, there is a problem writing it and the exact brand or another algorithm should be chosen. You can read and write these chips as many as thousands of times. WARNING – Before doing anything with the chip, read the next paragraph below.

Now, before writing anything to the chip, read the chip and save a backup of the file in case you need it for anything in the future. Believe me, many times many people had regretted it for not having a copy of the original file for whatever reason they need it later. Save it with the “.bin” extension (binary) and after you back up the file, erase the whole memory of the chip (fill it with FF’s) and finally, enter the VIN of your car, starting in the hex location 0062h ($0062) of the chip, throughout location 0072h ($0072), covering the 17 characters of the VIN number.

I recommend that you use the ASCII area to edit the memory because there you will see the characters you are entering as they are. If you use the HEX area, you will need to convert each character to HEX first, which is time-consuming and not very helpful in this case. When entering the VIN in the ASCII area, always use ALL CAPITALS!

After writing the VIN in the chip and reading it back to see if all is good, then you are ready to solder the chip back in the circuit. Make sure you align it in the same orientation where it was (where pin #1 is facing).

Finally, there is still one more step for this to work. You will need to disconnect the immobilizer circuit (transponder ECU or “Immobox”), which is under the steering wheel. It must be disconnected so it cannot send signals to the ECM, which might cause the engine to fail to start. Just pull the immobox connector plug and leave the wire hanging next to it in case you wish to re-enable it.