BMW Airbag Light Problems
Content
Does your BMW's airbag turn on and off? If your BMW's airbag light stays on, it means there is a problem with the Supplemental Restraint System (SRS) and the airbags may not deploy if you are involved in an accident.
In this article, you will learn how to troubleshoot BMW airbag lighting problems yourself using scanners such as the Foxwell NT510 for BMW and the Carly adapter. You will also learn about some of the most common problems that can cause a BMW airbag to deploy.
Symptoms, warning messages
Signs that BMW drivers notice when there is a problem with the airbag system.
- SRS Airbag Light on Dashboard
- Pass. Constraint message
“A malfunction in the passenger safety system affecting the airbag, pretensioner, or seat belt force limiter. Keep fastening your seat belt. Please contact your nearest BMW centre." - Constraint message
“Faulty airbag, belt tensioners and belt tension limiters. Make sure the seat belt is fastened despite the malfunction. Have the problem checked at the nearest BMW Service Center." - Airbag light flashing
The airbag indicator may turn on and off randomly.
How to Read Codes/Reset BMW Airbag System
Follow these instructions to read and clear codes from your BMW airbag control unit. Instructions apply to all 2002 and newer BMW models including 1st, 3rd, 5th, X1, X3, X5, etc.
What do you need
- OBD2 scanner that can diagnose BMW SRS module
- Foxwell NT510 for BMW
- carly for bmw
- Other BMW Scanners.
instructions
- Locate the OBD-2 port under the dashboard. Connect the scanner to the OBD2 port. If your BMW is from 2001 or earlier, you will need a 20-pin OBD2 adapter.
- Turn on the ignition. Do not start the engine.
- The scanner will turn on. Select the chassis/BMW model on the scanner.
- Select BMW - Control units - Body - Security system. You can read the airbag trouble codes by going to the SRS/restraint control unit.
- Clear the codes from the airbag control module. Go back one menu. Scroll down to clear trouble codes. Click YES on the next screen.
Additional notes
- Airbag codes can only be deleted if the code is saved. This means that the fault is stored in the memory of the SRS device, but the problem itself is no longer there.
- If you do not correct the problem that caused the air bag indicator/code to operate, you will not be able to clear the codes. They will return as soon as you restart the machine. Read the codes again and fix the problem. Then turn on the airbag indicator again.
- Most airbag trouble codes require a scan to clear the code and reset the indicator. In very rare cases, the airbag indicator will turn off as soon as you fix the underlying problem without using a scan tool.
- Disconnecting the battery will not reset the airbag indicator or reset any codes stored in the SRS/Airbag control module. Generic OBD2 code readers cannot clear the BMW airbag indicator.
- Always disconnect the battery before working on any airbag component.
- When using airbags, always stay two feet away from the airbag.
How to Reset BMW Airbag Light Using Carly
In this video you will learn how to read and clear the BMW airbag indicator using Carly for BMW.
Common Causes of a Malfunctioning BMW Airbag System
Without reading the codes, there is no easy way to find out the cause of the BMW airbag activation.
That being said, there are some common causes and problem areas that often cause the BMW airbag light to come on. We do not recommend replacing parts without first extracting airbag codes.
Passenger presence sensor
The #1 common problem that causes the BMW airbag light to come on is related to a faulty passenger seat weight sensor (also called occupancy sensor, child presence sensor, passenger mat, passenger sensor cushion seat).
The sensor is installed under the cushion of the passenger seat and determines if the passenger exceeds a certain weight. If the person does not exceed the weight limit (for example, a child), the passenger airbag will not deploy in the event of an accident, as this could injure the child. This sensor fails very often and is usually the culprit.
Typically, if the seat occupied sensor on your BMW is defective, you will receive a warning on the iDrive screen about a problem with the passenger airbag or with the passenger airbag disabled.
To fix this problem, you need to remove the seat and seat cushion. At the dealership, this problem will cost you more than $500. If you have DIY skills, you can replace the passenger seat sensor yourself. A replacement passenger seat sensor can be purchased online for less than $200. Take a look at this list of BMW passenger weight sensors. To replace the passenger weight sensor yourself, you will need a few basic tools and about two hours.
Many BMW owners install a so-called BMW Passenger Sensor Bypass. This makes the airbag system think the sensor is working properly.
It is important to understand that if you install a BMW weight sensor bypass and have an accident, the passenger airbag will deploy even if there is no passenger or child in the passenger seat.
In some countries, changing the restraint system may be illegal. Make this modification at your own risk!
Starting the car or changing the battery
The airbag light on your BMW may stay on if you change your car battery or turn on a dead battery.
A low voltage fault code (supply voltage) is stored in the SRS control unit.
This is due to the fact that the old battery stopped providing the required voltage (voltage dropped below 12 volts) or you disconnected the battery while the key was in the ignition. The airbag module will store codes, but they can be cleared using the BMW Airbag Scanner.
seat belt buckle
Another reason why the airbag light may stay on is that the seat belt buckle is not working properly. There is a small switch inside the seat belt buckle that can fail. When you start the car, it may detect that you are in the seat, but the airbag control unit may not receive a signal from the seat belt buckle.
Try pressing the seat belt buckle several times and check that the airbag indicator does not turn off. In some cases, the seat belt may not latch when it is inserted into the buckle.
Seat belt pretensioner
A common problem that causes the airbag to deploy is the BMW seat belt pretensioner. The pretensioner is used to tension the seat belt in the event of an accident. If the driver's or passenger's seat belt pretensioner fails, the airbag indicator will illuminate.
Replacing a BMW tensioner takes one to two hours. When you read trouble codes from the SRS, you get trouble codes that point to the tensioner.
Airbag light after crash
If your BMW is involved in an accident, the airbag indicator will remain on. Even if you replace a deployed airbag, the indicator will remain on. The fault data is stored in the airbag control unit and cannot be deleted even with the BMW airbag diagnostic tool.
To resolve this issue, you have two options. You can replace the airbag control unit in your BMW, which can be very expensive.
A cheaper alternative is to send the BMW airbag module to a shop, who can reset the BMW airbag control unit. They will erase the crash data from your BMW's airbag computer and ship the device to you. This solution does not require reprogramming the computer.
Just plug and play. This is much cheaper than replacing the airbag module and installing a new unit.
Faulty clock spring
If the airbag indicator stays on and the horn does not work, the clock spring is most likely defective. The clock spring is mounted on the steering column directly behind the steering wheel. To replace, you need to remove the steering wheel.
On some BMWs, such as the E36, it is built into the steering wheel, meaning that the steering wheel also needs to be replaced. When the spring (slip ring) of your BMW watch starts to fail, you may start to hear a strange noise (such as a rubbing sound) coming from the steering wheel as you turn it.
Airbag sensor disabled
If you are working near an airbag sensor and accidentally disable the sensor while the key is in the ignition and the vehicle is running, the airbag indicator light will come on. Always disconnect the battery when replacing the power window or front bumper.
To move the glass up and down to remove the adjuster, reconnect the air bag sensor before turning the ignition on. Otherwise, an error code will be stored. The good news is that there are several BMW airbag scanning tools that can help you clear the codes yourself.
free contact
The electrical wires under the driver's or passenger's seat may be damaged, or the electrical connection may be loose. Move the seats back and forth and look for the codes again. If the trouble codes change from real to original, the problem is with one of the electrical connectors.
Inspect the connectors and cables to make sure they are not exposed.
Other possible causes
Possible related problems that could be caused by the SRS indicator on a BMW include:
- seat belts
- Wires can be damaged, such as airbag wires under the seats. The airbag cables are bundled in the door panels. Wiring to main airbag module. Check the continuity of the circuit with a multimeter. If you find a damaged cable, repair it and wrap it.
- Faulty side impact sensor
- It is possible that the side impact sensor contacts are oxidized or loose. Disconnect the electrical connector. Clean them up and apply some dielectric grease.
- Damaged front impact sensor (bumper
- Perhaps the problem is that the car was in an accident or you had a job fixing the front of your BMW.
- door wiring harness
- This is not a very common problem, but it can happen. Cables connecting the door to the vehicle near the door hinges may be damaged.
- Faulty ignition switch
- On the BMW E39 5 Series, a faulty ignition switch can cause the airbag warning light to come on.
- Aftermarket stereo installation
- Updating or deleting places
- Remove or upgrade steering wheel
- Blown fuse
- rusty connector
- Body or engine work
BMW Airbag Reset Scan Tools
- carly for bmw
- Carly for BMW requires you to have a smartphone. You also need to purchase the Carly App for BMW Pro, which costs another $60 from the Google Play Store or the Apple Store. This also applies to new BMWs. This won't work on BMWs until 2002.
- Foxwell for BMW
- A hand-held BMW airbag scanner that diagnoses BMW vehicles from 2003 and newer. It is easy to use and does not require additional hardware. Just plug it into an OBD2 port and you are ready to read and clear codes.
- BMW Peake R5/SRS-U Airbag Scanner Reset Tool
- Works on an older BMW from 1994-2003.
- BMW B800 airbag scan
- One of the cheapest BMW airbag scanners. Supplied with a 20-pin connector. Works on an old BMW. Coverage of BMW vehicles from 1994 to 2003.
BMW Airbag Reminder
BMW has released several recalls related to airbag issues. If your vehicle is subject to a recall, your BMW dealer will fix the airbag problem free of charge. Your BMW does not need to have a valid warranty to be covered by the recall.
To check if your vehicle is affected by the BMW airbag recall, you can call your dealer. Another way to check if a BMW has been recalled due to airbag issues is to enter its VIN number and look up BMW reviews by VIN. Or find a BMW airbag recall by make and model here.
