Order a new BMW diamond-style remote key shell with a blank PCF7925 ID44 transponder chip. These are widely available on AliExpress and similar marketplaces at a low price. Many sellers also offer a key-cutting service — send them a clear photo of your existing key (or the cut code stamped on the lock) and they will ship it pre-cut, ready to use.

The EWS3 module is a small grey plastic box located under the steering column, above the pedals. Remove the lower steering column trim cover (a few screws and clips) to expose the unit.

Alternative (no disassembly): If you own a BMW Scanner 1.4 cable, you can read the EWS3 EEPROM directly through the OBD2 port without removing the module. This is the fastest route for straightforward add-key jobs, though OBD reading is not reliable on every EWS3 revision — bench reading remains the fallback.

Open the flip-top lid on the EWS3 housing. Inside, press the internal connector clip to release the PCB, then slide the board out of the case. The EEPROM chip is now exposed and ready for reading.

Connect your reader to the EWS3 PCB:

• AK90+: Plug-and-play. The kit ships with the correct clip/adapter for EWS3 — no soldering needed.
• Autel IM608 with adapter 114: Works, but you must solder one wire between the adapter and the PCB to complete the connection.

Read the EEPROM and save the dump to your computer. Always keep an untouched backup of the original file before making any changes — if anything goes wrong during writing, this is the only way to recover the original state of the immobilizer.

Use your key programmer to prepare a new key slot in the EEPROM dump, and write the corresponding data to the new PCF7925 ID44 chip.

Note from experience: I first tried to program the key directly with the Autel IM608, but the process repeatedly failed with "key writing failed". Switching to the AK90+ completed the programming on the first attempt without any error. If you hit the same wall on the IM608, the AK90+ is the reliable fallback for EWS3 and it's inexpensive enough to keep permanently in the toolbox.

Once the chip is programmed, insert it into the diamond key shell. At this point the key will crank and start the engine.

The transponder is now recognized by the immobilizer and the car will start — but the remote buttons will not yet operate the central locking. To teach the car the new remote:

1. Insert the new key into the ignition and turn to position ON.
2. Turn the ignition OFF.
3. Remove the key from the ignition.
4. Press and hold the LOCK button on the remote.
5. While still holding LOCK, press the UNLOCK button 3 times in quick succession.
6. Release the LOCK button.

The doors should briefly cycle to confirm the remote has been learned. I have full guide on how to program E46 remote on the website as well.