BMW Passenger Seat Mat Occupancy Sensor Bypass
One of the most common problems with BMWs is the airbag light turns on due to a defective passenger seat mat sensor (also referred to as passenger weight sensor, passenger mat sensor, passenger occupancy sensor). To fix this problem properly you need to replace the seat mat with a new BMW passenger seat mat.
Many members install what is called BMW passenger seat sensor emulator ( also known as seat mat emulator, seat occupancy detector bypass) which is not recommended. Before you install a bypass module, you should understand how it works and legal implications of installing one.
Before you start replacing any airbag components including the Seat Occupancy Mat, call your BMW dealer and check if there is a recall for that particular problem. If there is a recall your BMW dealer will fix the problem free of charge.
It is very common for airbag and restraint system to be recalled even for cars older than 10 years old. Another method that will allow you to check for open BMW recalls is to go online Check for recalls on NHTSA website. You can check by VIN or model. If there is an open recall take your car to the nearest BMW dealer who should fix the airbag problem for free.
If there is no recall, you need to properly diagnose BMW airbag light. It is highly recommended to perform an airbag system scan and retrieve any fault codes. Follow this guide to learn how to diagnose airbag problems.
What is BMW Passenger Seat Mat Emulator
Seat mat emulator is designed to simulate an adult passenger in the front passenger seat. Its main benefit is to make the passenger airbag deploy in case of an accident where otherwise it may not have deployed. It also allows you to clear any fault codes related to the passenger seat mat and therefore turn off the airbag light.
The BMW passenger weight sensor emulator may be referred to as BMW passenger airbag bypass. When you install a passenger weight sensor emulator, you are not bypassing the passenger airbag. Contrary to popular belief, the passenger airbag will always deploy in case of an accident. Assuming the rest of the restraint system is working correctly.
The problem with installing a BMW passenger seat emulator (bypass) is that it cannot detect if there is a child in the passenger seat. If you decide to install a BMW passenger restraint system bypass, never allow a child or back facing infant car seat to be in the front passenger seat. If the airbag deploys it can cause fatal injuries to the child.
Symptoms of defective BMW passenger airbag sensor
Typical symptoms of a defective passenger weight sensor on a BMW include the airbag light on, passenger seatbelt warning, and one of the following error messages.
- BMW Airbag Light On
- BMW Passenger Occupancy Sensor Failure
- Pass. restraint system waring on iDrive
- Passenger Restraint System Error
- Front Pass. Restraint System Fault
- Driver Restraint System Malfunction
- Restraint Sys. Malfunction/Defective
- Fault in Pass. Restraint System Affecting Airbag
- Fault Codes such as: 93C1, 93C2, 93C3
Installation BMW Passenger Airbag Seat Sensor Bypass
- Installing a BMW passenger seat mat emulator/bypass disables a safety feature and is not a recommended solution.
- BMW dealers and most mechanics will not support this fix.
- In some countries, it is illegal to modify the restraining system.
- Be responsible and comply with the laws in your country.
- Install a BMW passenger airbag bypass at your own risk.
- You may be responsible for any consequences resulting from the use of BMW seat mat emulator. Even after you sell the car.
- Start the car and move the passenger seat forward. Recline the passenger seat forward as much as possible.
- Next turn off the car and remove the key from the ignition.
- Locate the passenger seat mat sensor wires under the passenger seat. The plug is right under the seat as shown in the picture. Note that some models may have the connector right under the seat cushion. The occupancy mat sensor connector is wired to the seat mat control box.
- You will have a two or three wire connector right under the passenger seat. The wires are usually white and blue if you have the two wire connector.
If you have the three wires the wires will typically be white, red and brown and the connector itself will have four pins. Wire colors may change between models. If you have an X3 or Z4 model you will not have a connector. Which means you will have to cut the wires and solder the emulator wires.
- Press the connector and unplug the seat mat connector.
- Plug the seat mat emulator.
- Restart the car. If the airbag light remains on, read the codes from your BMW.
Seat Belt Emulator
Once you install a BMW passenger airbag seat mat bypass, your BMW will beep reminding the passenger to wear the seat belt. The problem is that there is no one sitting in the passenger seat but the car thinks there is now that the passenger seat emulator is installed.
The workaround to address this problem is to install a BMW seat belt emulator. If you install a seat belt emulator you are bypassing the passenger seat belt microswitch.
- Turn off the ignition.
- Locate the large yellow connector under the passenger seat.
- Unlock the connector. Pull the lock away in order to be able to pull away from the connector.
- Use a screwdriver to remove the red and black wires from the plug. Once the two wires are removed, you will need to plug the two emulator wires at the same location. If you have a vehicle in the US market, you will need to replace the white wire with red. Replace the blue wire with the black wire.
- Re-connect the electrical plug.
- After installation seat occupancy status will change to always occupied.
- Passenger airbag will deploy even if there is nobody sitting in the passenger seat.
- Passenger airbag will deploy even if there is a child or infant seat on the passenger seat. This can cause injuries to the child or infant.
- Do not allow children or infant car seat to be placed in the front passenger seat if a bypass module is installed.
- If you let other people drive your BMW, you should inform them that no child or infant car seat should be placed on the front passenger seat.
Frequently Asked Questions
Why is my airbag / SRS is still on after installing the emulator?
If the airbag light on your BMW is still on after the emulator is installed, you need to check for error codes. The emulator only bypasses a defective seat mat sensor. It does not fix all airbag-related problems. It also does not disable the passenger airbag.
Why do I need a passenger seat mat sensor?
Passenger seat mat sensor function is to detect if a child or infant seat is placed on the passenger seat. If an airbag is deployed and children are seated in the front seat, it can cause fatal injuries to children. To avoid such fatal injuries, car manufacturers equip cars with seat occupancy mat. the occupancy mat is installed underneath the seat cushion. The passenger occupancy sensor not only recognizes the presence of a person in the passenger seat but also detect the weight of the person by detecting the pressure on the passenger seat mat. This allows the airbag module to determine if the passenger should be deployed or not.
Will a BMW passenger bypass module disable the passenger airbag?
No. It will change status to Seat Occupied - Airbag Enabled. Always. When you install a BMW passenger seat mat occupancy sensor, you do not bypass or disable the airbag system. You are simulating a passenger in the seat and re-activate the airbag system making it deploy in case of an accident. The downside is that the passenger airbag will always deploy. Also, you no longer can have children sit in the front passenger seat.
Which sensor do I need?
- 1 series: E81 E82 E87 E88
- 3 series: E90 E91 E92 E93 M3
- 5 series E60 E61
- 6 series E63 - Fits after September of 2005
- 6 series E64 - Fits after September of 2005
- 7 series E65 - Fits after September of 2009
- 7 series E66 - Fits after 2004
- Z4 series E85 - Fits after November of 2003.
- X3 series E83 - Fits all variants.
- X5 series E70 - Fits all variants.
- X6 series E71 - Fits all variants.
- 1 Series E82 E88
- 3 Series: E90 E91 E92 E93
- 6 Series: E63 E64 From 10/2005
- 7 Series: E65 E66 From 2004
- X5 Series: E53 E70
- X3 Series: E83
- Z Series: E85 E86 E89
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