SRSCM (SRS Control Module)
SRSCM will detect front impact with front impact sensor, and side impact with side impact sensor, and determine airbag module deployment.
- DC/DC converter: DC/DC converter in power supply unit includes up/down transformer converter, and provide ignition voltage for 2 front airbag ignition circuits and the internal operation voltage of the SRSCM. If the internal operation voltage is below critical value setting, it will perform resetting.
- Safety sensor: Safety sensor is located in airbag ignition circuit. Safety sensor will operate airbag circuit at any deployment condition and release airbag circuit safely at normal driving condition. Safety sensor is a double contact electro-mechanical switch that will close detecting deceleration above certain criteria.
- Back up power supply: SRSCM has separate back up power supply, that will supply deployment energy instantly in low voltage condition or upon power failure by front crash.
- Self diagnosis: SRSCM will constantly monitor current SRS operation status and detect system failure while vehicle power supply is on, system failure may be checked with trouble codes using scan tool. (Hi-Scan)
- Airbag warning lamp on: Upon detecting error, the module will transmit signal to SRSCM indicator lamp located at cluster. MIL lamp will indicate driver SRS error. Upon ignition key on, SRS lamp will turn on for about six seconds.
- Trouble code registration: Upon error occurrence in system, SRSCM will store DTC corresponding to the error. DTC can be cleared only by Hi-Scan. However, if an internal fault code is logged or if a crash is recorded the fault clearing should not happen.
- Self diagnostic connector: Data stored in SRSCM memory will be output to Hi-Scan or other external output devices through connector located below driver side crash pad.
- Once airbag is deployed, SRSCM should not be used again but replaced.
- SRSCM will determine whether passenger put on seat belt by the signal from built-in switch in seat belt buckle, and deploy front seat airbag at each set crash speed.
- Side airbag deployment will be determined by SRSCM that will detect satellite sensor impact signal upon side crash, irrespective to seat belt condition.
Special Service Tools
SPECIAL SERVICE TOOL DESCRIPTION Tool (Number and Name) Illustration Use Deployment tool 0957A-34100A Airbag deployment tool Deployment adapter 0757A-38510 Use with deployment tool (DAB, PAB) Deployment adapter 0957A-2E110 Use with deployment tool. (PAB) Deployment adapter 0957A-3F100 Use with deployment tool. (SAB) Deployment adapter 0957A-38500 Use with deployment tool. (CAB, BPT) Dummy 0957A-38200 Simulator to check the resistance of each wiring harness Dummy adapter 0957A-3F000 Use with dummy (SAB) Dummy adapter 0957A-2D100 Use with dummy (PAB) Dummy adapter 0957A-1C000 Use with dummy (DAB, CAB, BPT)
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DAB: Driver Airbag
PAB: Passenger Airbag
SAB: Side Airbag
CAB: Curtain Airbag
BPT: Belt Pretensioner
General Precautions
Please read the following precautions carefully before performing the airbag system service. Observe the instructions described in this service information, or the airbags could accidentally deploy and cause damage or injuries.
- Except when performing electrical inspections, always turn the ignition switch OFF and disconnect the negative cable from the battery, and wait at least three minutes before beginning work.
Note. The contents in the memory are not erased even if the ignition switch is turned OFF or the battery cables are disconnected from the battery.
- Use the replacement parts which are manufactured to the same standards as the original parts and quality.
Do not install used SRS parts from another vehicle.
Use only new parts when making SRS repairs.
- Carefully inspect any SRS part before you install it.
Do not install any part that shows signs of being dropped or improperly handled, such as dents, cracks or deformation.
Scheme 39
- Before removing any of the SRS parts (including the disconnection of the connectors), always disconnect the SRS connector.
Airbag Handling And Storage
Do not disassemble the airbags; it has no serviceable parts. Once an airbag has been deployed, it cannot be repaired or reused.
For temporary storage of the air bag during service, please observe the following precautions.
- Store the removed airbag with the pad surface up.
- Keep free from any oil, grease, detergent, or water to prevent damage to the airbag assembly.
Scheme 40
- Store the removed airbag on secure, flat surface away from any high heat source (exceeding 85°C/185°F).
- Never perform electrical inspections to the airbags, such as measuring resistance.
- Do not position yourself in front of the airbag assembly during removal, inspection, or replacement.
- Refer to «AIRBAG DISPOSAL»(ref-674593-S27774134052014120300000) for disposal of the damaged airbag.
- Be careful not to bump or impact the SRS unit or the side impact sensors whenever the ignition switch is ON, wait at least three minutes after the ignition switch is turned OFF before begin work.
- During installation or replacement, be careful not to bump (by impact wrench, hammer, etc.) the area around the SRS unit and the side impact sensor. The airbags could accidentally deploy and cause damage or injury.
- After a collision in which the airbags were deployed, replace the front airbags and the SRS unit. After a collision in which the side airbag was deployed, replace the side airbag, the front impact sensor and side impact sensor on the side where the side airbag deployed and the SRS unit. After a collision in which the airbags or the side air bags did not deploy, inspect for any damage or any deformation on the SRS unit and the side impact sensors. If there is any damage, replace the SRS unit, the front impact sensor and/or the side impact sensors.
- Do not disassemble the SRS unit, the front impact sensor or the side impact sensors.
- Turn the ignition switch OFF, disconnect the battery negative cable and wait at least three minutes before beginning installation or replacement of the SRS unit.
- Be sure the SRS unit, the front impact sensor and side impact sensors are installed securely with the mounting bolts.
- Do not spill water or oil on the SRS unit, or the front impact sensor or the side impact sensors and keep them away from dust.
- Store the SRS unit, the front impact sensor and the side impact sensors in a cool (less than 40°C/104°F) and dry (less than 80% relative humidity, no moisture) area.
Connecting
Hold both connector halves and press firmly until the projection (C) of the sleeve-side connector clicks to lock.
Scheme 41
Warning Lamp Behavior After Ignition On
As soon as the operating voltage is applied to the SRSCM ignition input, the SRSCM activates the warning lamp for a bulb check.
The lamp shall turn on for 6 seconds during the initialization phase and be turned off afterward. However, in order to indicate the driver, the warning lamp shall turn on for 6 seconds and off for one second then on continuously after the operating voltage is applied if any active fault exists.
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- Active fault or historical fault counter is greater or equal to 10
- Normal or historical fault counter is less than 10
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SRSCM Independent Warning Lamp Activation
There are certain fault conditions in which the SRSCM cannot function and thus cannot control the operation of the standard warning lamp. In these cases, the standard warning lamp is directly activated by appropriate circuitry that operates independently of the SRSCM. These cases are
- Loss of battery supply to the SRSCM: warning lamp turned on continuously.
- Loss of internal operating voltage: warning lamp turned on continuously.
- Loss of Microprocessor operation: warning lamp turned on continuously.
- SRSCM not connected: warning lamp turned on continuously through the shorting bar.
Telltale Lamp Activation
The Telltale Lamp indicates the Passenger Airbag (PAB) enabled and disabled status based on occupant status of passenger seat. If the passenger seat is empty or occupied with child (or child seat), the Passenger Airbag is disabled and the Telltale Lamp is turned ON to inform the driver that the PAB is disabled. As soon as operating voltage is applied to the SRSCM ignition input, the SRSCM activates telltale lamp prove out. Occupant status information and telltale status are as below table.
| Occupant Status | Telltale Lamp | PAB |
|---|---|---|
| Empty | ON | Disabled |
| Child (Small Occupant) | ON | Disabled |
| Adult (Large Occupant) | OFF | Enabled |
| Defect | OFF | Enabled |
OCCUPANT STATUS
After ignition on, telltale lamp will turn on for 4 seconds and turn off for 3 seconds during the initialization phase and be turned off afterward until receipt of first valid suppression message from OCS system.