Installation instructions – seat occupancy sensor emulator – BMW i3 US

Seat mat emulator BMW i3 - installation

1. Turn the ignition off.

2. Under the passenger seat, locate the 4-pin mat plug with 3 wires:
– white
– brown with a white stripe
– red with an orange stripe.
It is placed in a big yellow connector which needs to be opened.

Yellow connector
Yellow connector after opening. Individual plugs visible - the first on the left, white, is the seat belt buckle plug; the first on the right, black, is the seat mat plug. Click to enlarge.

3. Disconnect the seat occupancy sensor plug and replace the mat wires with the emulator wires in the plug (using e.g. a small screwdriver to press the pin plates to remove the mat wires from the plug) as in the scheme below:

4. Connect the seat belt buckle emulator – click the link below to see the installation instructions:

Installation instructions – seatbelt buckle emulator BMW i3

5. Insert all plugs into the yellow connector in the same order as it was before  and close the connector.

6. After installing the emulators it is needed to remove the fault code using the appropriate diagnostic software.

Seat occupancy sensor plug
Click on the picture to enlarge
Seat mat emulator connected. Seat belt emulator not connected yet (visible white plug)
Emulator connected. On the left, wires of the original seat occupancy sensor are visible (they stay disconnected). Click to enlarge

We encourage you to watch a short installation video of the emulator in BMW F Series - the installation looks very similar in BMW i3:

WARNING. After installing the emulator, do not transport a child in the child seat on the front seat, because the airbag will always work in case of an accident – the car functions as if the passenger seat was always occupied by an adult.

The emulator should be installed by a mechanic or a person qualified in the SRS systems.

In most BMW models, the seat occupancy sensor is placed only in passenger side seat. Therefore, you should look for the plug under the passenger seat, not the driver. The exception is BMW 7 Series, in which seat mat is placed in the driver’s, passenger’s and in the rear seat.

If you can’t find the plug, see the pictures above. Contact us if you need any help.

If there is 2-wired seat occupancy sensor in the car don’t try to connect the emulator – it fits only 3 wired seat mat.

Reset the fault code using proper diagnostic software.

If resetting the fault does not help, make sure that the warning light is caused by faulty seat occupancy sensor – the airbag warning light indicates a failure in the safety system and it does not necessarily have to be seat mat. The seat occupancy sensor emulator bypasses faulty seat occupancy sensor only – not other parts of the srs system. Quite often cause of the airbag warning is a faulty seat belt tensioner. That can also be other parts (airbags, BST, airbag control unit etc.) or a defect in the car installation – perform accurate computer diagnostics using a good software – cheap / non-original scanners often show different errors than they actually do.

There are a lot of different situations and problems in cars – if you have questions and need additional information, please contact us.

Connect the seat belt emulator – wires red and black.

After connecting the seat occupancy sensor emulator, the airbag control unit (and car computer) “sees” the front passeneger seat as always occupied (even if there’s no passenger).
Therefore, cars equipped with seat belt fastening sensor will report a request to fasten the seat belt (the unfastened seat belt warning light/sound appears). Connecting the seat belt emulator will solve the problem (car computer will “see” the passenger seat belt as always fastened).

If you are using a universal tester/scanner, it may happen that even after erasing the errors from the airbag control unit, the airbag warning light will still be on.
In this situation, performing a full scan of all systems in the car helps. Usually already during the scan the light disappears.

This problem rather doesn’t occur with professional diagnostic computers dedicated only for BMW (they are not cheap mobile applications or programs downloaded from the Internet).