Why does the airbag light come on
Content
Airbags (airbag) are the basis of the rescue system for the driver and passengers in case of accidents. Together with the belt pretensioning system, they form the SRS complex, which prevents serious injuries in frontal and side impacts, rollovers and collisions with large obstacles.
Since the pillow itself is unlikely to help, the control unit will declare the impossibility of its operation in case of any failures of the entire system.
When does the Airbag light on the dashboard come on?
Most often, a malfunction indicator is a red pictogram in the form of a man fastened with a belt with a stylized image of an open pillow in front of him. Sometimes there are letters SRS.
The indicator lights up when the ignition is turned on to indicate the health of the corresponding LED or display element, after which it goes out, and sometimes the icon flashes.
Now they refuse such a regime, too often it became a reason for panic, the master does not need this, and the ordinary driver should not self-medicate such a responsible system.
Failure can occur in any part of the system:
- threads of squibs of frontal, side and other airbags;
- similar emergency belt tensioners;
- wiring and connectors;
- shock sensors;
- sensors for the presence of people on the seats and limit switches for seat belt locks;
- SRS control unit.
Fixing by the self-diagnosis function of any malfunctions leads to the shutdown of the system as potentially dangerous and informing the driver about it.
Is it possible to drive like this?
The car engine and other components responsible for the movement are not turned off, technically the operation of the car is possible, but dangerous.
The modern bodywork is repeatedly tested to protect people in a variety of situations, but always with the SRS system working. When it is disabled, the car becomes dangerous.
The high rigidity of the body frame can turn in the opposite direction, and people will get very serious injuries. Tests on dummies showed numerous fractures and other injuries even at medium speeds, sometimes it was obvious that they were incompatible with life.
Even with serviceable airbags, failed belt tensioners caused dummies to miss the working area of the opened airbag with the same consequences. Therefore, the integrated performance of the SRS is important, clearly and in normal mode.
Nothing will prevent you from getting to the place of repair, but this will require maximum care in choosing the speed and position on the roadway.
Malfunctions
When a fault is displayed, the unit memorizes the corresponding error codes. There are not so many of them, mainly these are short circuits and breaks in the circuits of sensors, power supply and executive cartridges. The codes are read using a diagnostic scanner connected to the OBD connector.
Most often, nodes that are subject to mechanical damage or corrosion suffer:
- a cable for supplying signals to the driver's front airbag hidden under the steering wheel, which experiences multiple bends with each turn of the steering wheel;
- connectors under the driver's and passenger seats - from corrosion and seat adjustments;
- any nodes from illiterately carried out repair and maintenance operations;
- charge ignition devices having a long but limited service life;
- sensors and electronic unit - from corrosion and mechanical damage.
Software failures are possible when the supply voltage drops and fuses blow, as well as after replacing individual nodes without their correct registration in the control unit and on the data bus.
How to extinguish the indicator
Despite the fact that the airbags cannot be deployed in emergency mode, all dismantling procedures must be carried out with the battery disconnected.
Applying power and turning on the ignition eliminates interference with the wiring or mechanical impact on the elements of the system. You can only work with a scanner.
After reading the codes, the approximate localization of the malfunction is determined and additional verification procedures are performed.
For example, the resistance of the igniter is measured or the state of the steering column cable is visually monitored. Check the condition of the connectors. Usually they and the supply harnesses in the SRS system are marked in yellow.
After replacing the defective elements, the newly installed ones are registered (registration), and the errors are reset by the scanner software utilities.
If the malfunction remains, then resetting the codes will not work, and the indicator will continue to glow. In some cases, only current codes are reset, and critical ones are stored in memory.
The indicator must be lit when the ignition is switched on. On cars with an unknown history and a completely faulty SRS, where there are dummies instead of pillows, the light bulb can be drowned out or completely eliminated through the program.
More sophisticated deception schemes are also possible, when decoys are installed instead of igniters, and the blocks are reprogrammed. To calculate such cases, a great experience of the diagnostician will be required.
