The SRS consists of: an airbag on the driver's side, located in the center of the steering wheel and containing a folded cushion and gas generator unit; an airbox on the passenger side, located in the instrument panel and containing a rolled-up airbag and a gas generator unit; side air chambers located in the backs of the driver and front passenger and containing folded pillows and a gas generator unit.
The SRSCM control unit is located on the floor of the vehicle under the heater core and controls the airbag system and includes: an accelerometer that detects vehicle deceleration; spiral wire (spring), located in the steering column; electrical circuits and connectors; knee buffer located under the steering column. The coiled wire transmits the signal regardless of the position of the steering wheel.
The SRSCM determines the moment of collision based on information from the accelerometer, which constantly monitors the vehicle's acceleration.
The airbag deploys in a moderate to severe frontal or near-frontal collision.
The pyrotechnic gas generator converts the control electrical signal into an ignition signal, causing the powder to decompose, inflating the airbag bag.
Only specially trained personnel should be allowed to service airbags or SRS components. When servicing the SRS, extreme care must be taken to avoid personal injury from unauthorized deployment of driver or front passenger airbags.
Precautionary measures
Failure to properly deactivate or service the airbag system could result in unauthorized airbag deployment and serious injury. Also, improper maintenance of the airbag system may result in the airbag not deploying in a collision.
Before performing any maintenance, including removing or installing system components, carefully follow these guidelines.
1. Before servicing the airbag system, make sure that at least 30 seconds have passed after the ignition is turned off and the wire is disconnected from the negative terminal of the battery. The airbag system is equipped with an emergency power source that allows the airbags to deploy if the battery wires are disconnected in an accident. The time during which the emergency power supply powers the airbag system is 150 ms.
2. When the wire is disconnected from the negative terminal of the battery, the memory of the clock and sound systems is erased. Extract information from the sound systems before you begin. After completing the work, set the time on the clock and re-install the sound systems.
3. Signs of an airbag system failure are difficult to check, so diagnostic codes become the most important source of information when troubleshooting.
4. When troubleshooting the airbag system, check the stored fault codes before disconnecting the battery.
5. Do not use spare airbag parts from other cars.
6. Do not disassemble or repair airbag system components.
7. If any SRS component has been dropped or has cracks, dents, or other defects in the housing, bracket, or connector, replace them with new ones.
8. After carrying out the work, check the airbag system.
In some cases, the airbag warning light circuit may be broken by another circuit malfunction. Therefore, if the airbag warning light stays on, check that all DTCs have been cleared from memory.
9. When carrying out electric welding, be sure to disconnect the wire from the negative terminal of the battery.
Module (DAB, RAB, SAB)
DAB modules (driver's airbag), RAV (front passenger airbag), DSAB (driver's side airbag) and PSAB (passenger side airbag) consist of an opening device and a pillow. Opening device (gas generator) located in the airbag. If a frontal collision is severe enough to short the SRSCM sensor, current will begin to flow through the airbag deployment circuit. This current ignites the gas generator charge and the airbag deploys.
1. When removing the airbag or working on a new airbag, it must be positioned so that the surface of the airbag is directed upwards. In this case, the double lock connector lock lever must be in the locked position.
2. Never measure the resistance of the airbag igniter, as this may cause it to fire.
3. Store airbags at a temperature not exceeding 93°C, free from moisture and electrical interference.
4. When using electric welding, disconnect the connectors from the airbag before starting work.
SRS wiring harness
The SRS harness is located inside a yellow tube that is different from the wiring harnesses of other systems. The connectors on the DAB, PAB, DSAB, PSAB and BPT side have jumpers that complete electrical circuits when the connectors are disconnected, preventing unwanted deployment of the airbag.
SRSCM warning lamp
The SRS warning lamp, located in the instrument cluster, is controlled by the SRSCM.
With some faults, the SRSCM cannot function and thus cannot control the operation of the warning lamp. In these cases, the lamp is directly activated from the corresponding circuit, which operates independently of the SRSCM.
1. In the absence of voltage supplied to the SRSCM, the lamp is constantly on.
2. In the absence of internal operating voltage, the lamp lights up constantly.
3. If the SRSCM is not connected, the lamp is turned on via a jumper in the harness connector.
Coil spring
The coil spring consists of two twisted coils. It is installed between the steering column and the steering wheel and allows the steering wheel to rotate while keeping the safety circuit electrically in contact at all times.
The steering wheel must be correctly installed on the steering column with the coil spring set to the neutral position, otherwise a broken wire or other malfunctions may occur.
Driver airbag and coiled wire
Withdrawal
1. Disconnect a wire from the negative plug of the storage battery.
Warning! Before servicing the airbag system, make sure that at least 30 seconds have passed after the ignition is turned off and the wire is disconnected from the negative terminal of the battery.
2. Remove the steering wheel cover and align the driver's airbag mounting bolts with a hex wrench.
3. When disconnecting the airbag coil wire electrical connector, place a retainer on the connector facing outward.
Warning! When disconnecting the coiled wire electrical connector from the airbag, do not use force.
4. Remove the driver's airbag.
Warning! The removed airbag must be stored in a clean, dry place, face up.
5. Puller 09561-11002 remove the steering wheel.
Do not hit the steering wheel as this may damage the steering column protection mechanism and reduce the driver's protection in the event of a frontal collision.
Airbag check
If there are any defects, the airbag must be replaced.
Warning! Do not attempt to measure the resistance of the airbag pyrotechnic inflator circuit as unauthorized deployment of the driver's airbag may occur.
1. Check the airbag cover for dents, cracks or deformation.
2. Check up an airbag on lack of indentation, splitting or deformation.
3. Check the condition of the hooks and connectors for damage, oxidation of the connector pins, and damage to the wiring harness.
4. Check the airbag pyrotechnic inflator housing for dents, cracks, or deformation.
5. Place the airbag against the steering wheel to check its alignment and suitability.
Spiral wire test (springs)
1. If there are any defects, the coiled wire must be replaced.
2. Check the electrical connectors and the yellow protective tube for damage and oxidation of the connector pins.
Front passenger airbag
Withdrawal
1. Do not disassemble or repair airbag system components.
2. If the airbag has been dropped or has been exposed to water, lubricants, or oil, or if there are cracks, dents, or other defects in the housing or connector, replace the airbag.
3. The removed airbag must be stored in a clean, dry place, face up. Do not place objects on the airbag that could cause serious injury when the airbag deploys.
4. Do not expose the airbag to temperatures above 93°C.
5. A non-deployed airbag assembly must only be located in accordance with prescribed procedures.
6. Do not attempt to measure the resistance of the airbag pyrotechnic inflator circuit as unauthorized deployment of the driver's airbag may occur.
7. After the airbag has deployed, it must be replaced along with the wire that has been exposed to the gases of the pyrotechnic gas generator.
Order of execution
1. Disconnect a wire from the negative plug of the storage battery.
Warning! Before servicing the airbag system, make sure that at least 30 seconds have passed after the ignition is turned off and the wire is disconnected from the negative terminal of the battery.
2. Remove the glove box.
3. Disconnect the airbag electrical connector.
4. Remove the instrument panel and airbag.
5. The outer layer of the front passenger airbag is integrated with the instrument panel, so when the airbag deploys, the instrument panel must be replaced.