Rick's Free Auto Repair Advice

Why is my airbag light on

How to diagnose and fix an Airbag light on condition

Got an Airbag light on and you just want to clear the airbag code? vw warning icon airbagI’ve got news for you; the airbag system conducts a check every time you turn the key. If you clear the code and the light comes back on, THERE’S a problem with the airbag system.

What causes and airbag light on condition?

The supplemental restraint system (SRS) consist of at least one airbag, some type of impact or g-force sensor, seat belt pretensioners, passenger seat detection device, and in some cars, side airbags and knee bolsters. The main SRS computer tracks the condition of all the components and sensors when you start the car and while you’re driving. If it detects a fault, it sets the SRS or airbag light on condition.

airbag light on

Crash sensor

In many cases, the cause can be as simple as a poor connection at the

airbag light on

Occupant seat detection sensor

passenger seat detection device. In those instances the fix can be as simple as powering down the airbag system and disconnecting and reconnecting the connector. However, other times it can require replacing the seat detection device.

airbag light on, occupant seat sensor

Toyota occupant seat detection

Where to start your diagnosis of an airbag light on condition?

It all starts by getting the trouble code. If you skip this step, you’ll replace perfectly good parts and I guarantee you, you’ll wind up back at the starting point trying to get the trouble code you should have gotten in the first place.

Get the trouble code with a scan tool

Look, if you want to repair your own vehicles you simply have to own the right tools or rent them if you don’t have them. Owning a scan tool is pretty much a given. It’s just as critical as owning a socket set. Sure, you can run it over to the auto parts store and let them scan it for you, but auto parts scan tools usually only read generic powertrain codes. They DON’T read manufacturer specific codes, chassis “C”codes, body “B” codes, or digital “U” communication codes.

Why? Because the auto parts store don’t want the liability of reading an airbag code or giving you advice on how to fix it. Wrong advice can get someone killed.

Here’s an example of the number of airbag trouble codes.

B1901 Air Bag Crash Sensor #1 Feed/Return Circuit Short To Ground
B1902 Air Bag Crash Sensor #1 Ground Circuit Failure
B1903 Air Bag Crash Sensor #1 Ground Circuit Short To Battery
B1904 Air Bag Crash Sensor #2 Feed/Return Circuit Failure
B1905 Air Bag Crash Sensor #2 Feed/Return Circuit Short To Battery
B1906 Air Bag Crash Sensor #2 Feed/Return Circuit Short To Ground
B1907 Air Bag Crash Sensor #2 Ground Circuit Failure
B1908 Air Bag Crash Sensor #2 Ground Circuit Short To Battery
B1909 Air Bag Crash Sensor #2 Ground Circuit Short To Ground
B1910 Air Bag Diagnostic Monitor Ground Circuit Failure
B1911 Air Bag Diagnostic Monitor Ground Circuit Short To Battery
B1912 Air Bag Diagnostic Monitor Ground Circuit Short To Ground
B1913 Air Bag Driver/Passenger Circuit Short To Ground
B1914 Air Bag Crash Sensors #1 / #2 Circuit Short To Ground
B1915 Air Bag Driver Circuit Failure
B1916 Air Bag Driver Circuit Short To Battery
B1917 Air Bag Memory Clear Circuit Failure
B1918 Air Bag Memory Clear Circuit Open
B1919 Air Bag Memory Clear Circuit Short To Battery
B1920 Air Bag Passenger Circuit Failure
B1921 Air Bag Diagnostic Monitor Ground Circuit Open
B1922 Air Bag Safing Sensor Output Circuit Short To Battery
B1923 Air Bag Memory Clear Circuit Short To Ground
B1924 Air Bag Internal Diagnostic Monitor Fault or System Disarm Fault
B1925 Air Bag Passenger Circuit Short To Battery
B1926 Air Bag Passenger Pressure Switch Circuit Failure
B1927 Passenger Side Airbag Fault
B1928 Air Bag Safing Sensor Output Circuit Failure
B1929 Air Bag Safing Sensor Output Circuit Open
B1930 Air Bag Safing Sensor Output Circuit Short To Ground
B1931 Air Bag Crash Sensor #1 Feed/Return Circuit Failure
B1932 Air Bag Driver Circuit Open
B1933 Air Bag Passenger Circuit Open
B1934 Air Bag Driver Inflator Circuit Resistance Low on Squib
B1935 Air Bag Passenger Inflator Circuit Resistance Low on Squib
B1936 Air Bag Driver Circuit Short To Ground
B1937 Air Bag Passenger Pressure Switch Circuit Open
B1938 Air Bag Passenger Circuit Short To Ground
B1939 Air Bag Passenger Pressure Switch Circuit Short To Ground
B1941 Air Bag Crash Sensor #1 Feed/Return Circuit Open
B1942 Air Bag Crash Sensor #2 Feed/Return Circuit Open
B1943 Air Bag Crash Sensor #1 Ground Circuit Short To Ground
B1944 Air Bag Crash Sensor #1 Ground Circuit Open
B1945 Air Bag Crash Sensor #2 Ground Circuit Open

Power down the airbag system before touching any component

Each car maker has their own power down procedure. Just about every one requires disconnecting the battery. But you should be aware that disconnecting the battery on a late model vehicle can cause it to lose critical calibrations like throttle body, window, steering angle, etc. So, if you try to do your own airbag repairs, you may wind up with a car that won’t start after because it’s lost its throttle body calibration. In other words, get a shop manual and learn how to do a steering angle and throttle body, memory seat, anti-pinch window relearn procedure.

Don’t ignore the airbag light on condition

Once the SRS light turns on, the computer keeps track of how many times you started the car with the light on. So, if you carry a passenger and that passenger gets injured because the airbag didn’t go off, you’re going to get sued for every penny you have. The injured party’s lawyer will have the computer read and they’ll present that evidence at trial that you knowingly transported a passenger with a faulty airbag system. See where this is going? And the car makers get off scot free too because they use the number of starts to proved that it was YOUR fault the airbags didn’t go off. You knew they weren’t working (can’t claim the light didn’t come on because it always comes on when you turn the key) and yet your drove with a disabled safety features. So bottom line, quit whining. Stop asking how you can “trick” the safety inspectors. Stop asking how you can bypass the system. You can’t. Just get it fixed.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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