If the airbag sensor detects an impact from a severe frontal collision, the pretensioners rapidly retract the front seat belts to keep the belts firmly in place for front seat occupants.
The front seat belt pretensioners operate even when there are no passengers in the front seats.
Pic. 1.101. Front seat belt pretensioner warning light
This warning lamp comes on when the ignition key is turned to the «ON». It goes out after about 6 s. This means that the front seat belt pretensioners are working properly.
This warning system monitors the airbag sensor assembly, front airbag sensors, side airbag sensors, side and curtain airbag sensors, curtain airbag sensors, driver's seat position sensor, driver's seat belt buckle switch, front seat belt pretensioner assemblies, blowers, pilot lamp, internal wiring system and power supplies.
Pic. 1.102. Front seat belt pretensioner system
The front seat belt pretensioner system consists of the following main components, the location of which is shown in Figure 1.102:
- 1. Front airbag sensors.
- 2. A control lamp of system SRS.
- 3. Knots of a pretensioner of seat belts of forward seats.
- 4. Node sensors airbags.
The seat belt pretensioners are controlled by the airbag sensor assembly. The airbag assembly consists of an allowable impact sensor and an airbag deployment sensor.
When the front seat belt pretensioners are deployed, operating noise may be heard and a small amount of smoke-like gas may be emitted. This gas is harmless and does not indicate a fire.
After the front seat belt pretensioners have deployed, the seat belt pretensioners remain locked.
The following are the safety warning lights that indicate a problem with the seat belt pretensioner.
- The warning light comes on when the key is turned to the «ON» or remains lit for more than 6 s.
- The indicator light comes on while driving.
- The front seat belt does not retract or does not retract due to a malfunction or activation of the front seat belt pretensioners.