Reprogramme the BMW 3G EWS Alarm System

Some years ago i bought a BMW Z3 as a fun weekend car, but the only thing wrong with it was the Alarm System didn't work and wouldn't alarm nor operate the central lockiing. I booked the car into the local BMW dealer and was told that it needed a new alarm CCU at a ridiculous cost. Undeterred I trawled the internet and found some posts on the alarm system.

I looked at what I was being advised to do and the physicals of the system and came up with my own diagnosis and fix. Believe me - it worked first time, so here are the instructions that I wrote

If you drive an E36 or Z3 then you will know all about the battery going flat if you leave the car for more than a week. The chances are that you’ve also found yourself locked out of your car when the alarm remote has decided to fail. Unlike later models which have the alarm integrated into the car’s electronic system, the E36 3 series and Z3 range used a unit manufactured by Gemel in Italy, the company also manufactures the Serpi Star and Sigma brands. This unit goes by different names in different versions but one of the most popular is the “BMW 3G EWS” also known as the BMW Digital Alarm System. This was usually a dealer fit option when you bought the car. The system is well proven and works well enough until you either damage the remote and don’t have a spare or you let the car battery discharge. Since these systems use a rolling code, you can’t disable the alarm without the remote, and you can’t code the alarm unless you can deactivate it – so its a catch 22 situation.

Before you accidentally send your only remote through the washing machine and the system leaves you locked out, buy a new one from your friendly BMW garage and follow our instructions to code it to your system.


1. The Alarm module should be fitted behind the glove box, which means that you have to remove it. Start by removing the 2 screws in the top corners of the dash vents. On the Z3 you just have to remove the screws located around the glove box and adjacent to the centre console.

2. Then prise out the plastic covers and remove the other two screws, don’t worry too much about damaging the plastic covers as they are only 10p each.

3. Two more screws are found at the bottom edge of the glove box aperture and two more underneath. Prise out the glove box light and remove the bolt hidden above it. With this removed the whole glove box frame can slide out.

4. With the glove box out of the way, you should be able to see the Alarm Control Module. On the 3 series it is located on the left behind a metal cover, whilst on the Z3 it is located straight in front of you again behind a metal cover, you will need an octagonal screwdriver to remove the cover, depending on the dealer it may have 2 screws holding it in place.

5. The Control Module consists of two units, one is the receiver which has 1 wire attached to it and is plugged onto the main receiver module. The receiver module can be unplugged from the main body of the unit. HOWEVER it may cause the alarm to activate !!!!!. BEWARE

6. With the module easily accessible, you’ll need to find the coding switch which can be accessed through a hole in the casing, this normally has a rubber grommet covering it. Make a note of which position it’s in as you’ll need to move it to put the unit into “coding mode”.

7. Before you go any further make sure that you’ve bought the right remote from BMW. They normally have them in stock but take your one to them to make sure you get the right model. The part number is 82 92 9 404 882 and costs around £30. They are also sold quite frequently on eBay.

8. With the coding switch moved to the coding position and the car’s ignition off, press the red button on the remote. Move the switch back from the coding position and try your remote. If you’ve done everything right it should work and you can now put everything back again.

If your remote fails and your alarm is still activated, you can deactivate the alarm with the “secret code” which should have been provided when the alarm was fitted by the dealer.

· Turn on the ignition, wait 30 seconds, · turn it off again and count the flashes on the LED. · If your code is ‘12345’, · wait for 1 flash and press the LED, · then turn the ignition off and on again, · wait for 2 flashes, · turn the ignition off and on again etc. · until the alarm is deactivated.

Active Alarm Mode

If your alarm is stuck in the Active Mode - follow these instructions

1 Discovered from the workshop foreman at another BMW dealer that the remotes cannot be recoded if the alarm is in an 'active' state. He suggested trying to buy another remote matched to a new receiver unit (£63) which is separate from the alarm module and can be unplugged from it. He said there was apparently a way of 'tripping' the earlier systems to switch them off and code the remote controls but that it wasn't possible on the 3G. And that buying a matched remote and receiver would be difficult or impossible anyway.

2 I investigated it further and decided there must be a way of 'tripping' thesystem to deactivate it.

3 Egged on by a mate known for his reckless attitude to automotive electrical troubleshooting, I removed the receiver module from its housing and plugged it back into the alarm module, allowing access to the pins during operation.

4 With nothing to lose, we tried randomly connecting a couple of the pins which made the hazard lights flash twice, just as they do when arming the system.

5 Realising we were on to something, we used a small piece of wire to short all the pins to each of the end pins in turn, whereupon at one point the doors suddenly locked and unlocked. Short out pins 2 and 4, then pins 2 and 5. Do not worry as you can’t damage the unit if you short out the wrong pins.

6 Followed the coding procedure as advised by BMW:

- Flick the coding switch

- Press the red button on one remote then the grey button on the next and so on to a maximum of four remotes

- Flick the switch back

7 Amazingly it worked. Installed the alarm module neatly, replaced the glove box and saved £200.

Another Method (untried)

I found the instructions below on an American website, I haven't tried them as my method above works on all the cars that I have tried.   BMW REMOTE KEYLESS ENTRY SYSTEM REPROGRAMMING PREPARATION:

1. Close all doors, trunk, and hood.

2. The security system must be in 'disarm' mode. The key must be removed from the ignition key slot. ENTER CODE-LEARNING MODE:

3. Open the trunk and leave it opened.

4. Open the driver's door and sit in driver's seat.

5.Close the driver's door.

6. Cycle the ignition switch five times between the 'OFF' position and position, (ignition 'ON', all dash warning lamps will illuminate). The red status LED will illuminate continuously, and the siren will 'chirp' once, to indicate that the codelearning mode has been initiated.


7. Open driver's door. (remain seated in driver's seat). 8. Close driver's door. 9. Press and release any button on the remote you wish to register into the system. the status LED will shut off momentarily to indicate that one ID code has been registered.

10. Repeat 7 through 9 to register the remaining three ID codes. EXITING CODE-LEARNING MODE:

11. Open driver's door, and exit from vehicle, leaving the door opened.

12. Close trunk.

13. Close driver's door. The LED will turn off and the siren will 'chirp' twice.

14. The initialization procedure is now completed; test all remotes to confirm operation.

How To

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