Installing a Chip on the 1993-1995 BMW 325i/525i

This document is about installing a performance chip on a 1993 – 1995 BMW 325i or 525i ecu.

First of all, you will need to locate the ECM and uninstall it from the car. The ECM (Motronics DME) is located under the hood, in the engine compartment, below the right wiper assembly (passenger side).


Refer to the drawing above; Facing towards the windshield, at the upper right corner of the vehicle (passenger side), you will see a soft foam cover. Remove the three black plastic buttons that are on top and pry out the plastic tab centers to remove them and then remove the insulated foam cover.


Now, you will see a hard plastic cover. Remove this cover by removing the four top screws.


You will see the ECU box attached to a wire harness. Remove it by pulling it out. The ECU will just slide out.

Do not disconnect the harness until the ECM is completely removed. For disconnecting the harness, just pull out the lock lever, in the direction showed by the red arrow in the picture above.

E34 Model


If your BMW is the E34 chassis model, the ECM is located under a plastic cover, as showed by the red arrow in the picture above.

Chip Installation

There are six tabs holding the ECM over at the bottom of the ECM. Using a small and sharp flat screwdriver, CAREFULLY bend the tabs away, so you can take the cover out from its place. Please take EXTRA precautions when doing this and also when reinstalling the cover, to (1) avoid cutting your hands or fingers if the screwdriver slips and (2) avoid breaking the tabs, as they have proven to be very, very fragile and fracture very easily at the apex.

Now, inside of the ECM, there is a white plastic cover on top of the EPROM chip. It looks like an “H” (picture below). The chip bellow it is the chip to be replaced, so please unsnap the plastic cover and BEFORE removing the chip, please note the alignment of its pin #1, so the new chip can be inserted the same way (see a note about this at the end of this document).

Take out the chip by using the same small flat screwdriver and slide it CAREFULLY under the chip for slowly prying it out of place, little by little, from both sides, one at a time. If you have a simple chip pulling tool, you may use it instead. When prying the chip upwards, be careful not to brake the plastic socket beneath the chip.

Now install the performance chip, by inserting it in the socket. For doing this, point pin #1 to the same corner as the old chip, then, carefully aligning all the pins into the holes and push it down firmly, securing it on place. Re insert (snap) the plastic “H” shaped plastic cover. Now you are ready to put back the ecu cover, reinstall the ecu and enjoy the new performance.

A word of caution about installing chips

Need a great chip for your 1994-1995 BMW 325i? The chip below is for the Bosch 0 261 200 413 DME (ECM). It compares with chips made by Jim Conforti.

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13 Responses

  1. Olechka-persik says:

    Thanks for post. Nice to see such good ideas.

  2. Henry Collins says:

    Hey I bought one of those from racingchips. They are just great. It has my 325i pulling hard now. thanks!

  3. Neftali Hernandez says:

    sorry, I had a question about the chip on Will post it in the right page. Thanks

  4. admin says:

    Henry, I’m glad you could take advantage of our advice.

    Neftali, no problem. As soon as you post your question, we will be more than glad to help.



  5. KrisBelucci says:

    Hi, good post. I have been wondering about this issue,so thanks for posting. I’ll definitely be coming back to your site.

  6. Dmitry says:

    Very nice post 🙂 Thank you for sharing

  7. G. Capano says:

    Good Information. Is it the same procedure for 2001 325i?

  8. Richard says:

    No. This doesn’t apply for any 1996 and later BMW models. Those OBD-II models does not have a replaceable chip like earlier OBD-I models do.

  9. G. Capano says:

    There are places that sell for the BMW 2001 325i on eBAY. Your 1996 look somewhat similiar to my 2001. I think the third diagram look familiar.

  10. Richard says:

    Yes, the circuits might look similar, but unfortunately the chip depicted here is not available in the 2001 model’s computers.

    On eBay what they offer are mostly resistors in a box, unless they are selling a reprogrammable unit, not just a box with 2 to 6 wires attached to it.

    The reprogramming approach for these ecus is different and will include using special hardware and equipment.

  11. G. Capano says:

    Okay I think you enlighten me. There are chipa and there are resistors.

    Do resistors act the same as chips??

  12. Richard says:

    No, not at all. You will find interesting the following article on this blog:

    Resistors Vs Chips



  13. limewire says:

    wow sweet stuff dude.

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