Block Diagram
CAN abbreviations
| 15 | Ignition ON (terminal 15) | A96_L | Curtain airbag, driver |
|---|---|---|---|
| A24 | Driver's airbag | A96_R | Curtain airbag, passenger |
| A62 | Passenger's airbag | A105 | Steering column electronics module |
| A66_L | Driver's side airbag sensor | Y127_L | Seat belt tensioner, rear left |
| A66_R | Passenger's side airbag sensor | Y127_R | Seat belt tensioner, rear right |
Block Diagram (Continued)
| 31 | Ground (terminal 31) | Y129 | Seat belt tensioner, passenger |
|---|---|---|---|
| A23 | Driver's seat electronics module DSM | A96_D | Side airbag, driver |
| Y128 | Seat belt tensioner, driver | A96_P | Side airbag, passenger |
| Sxx | Seat belt tensioner switch, driver | A144 | Navigation system |
| A65 | Airbag control unit SDM | A158 | Carphone |
| A76 | Passenger's seat |
Function Table
Wiring harness plug X1 = 30-pin
Wiring harness plug X2 = 75-pin
| Terminal | Description | Source | Destination |
|---|---|---|---|
| X1-1 | Ground (terminal 31) | Ground | SDM |
| X1-8, X1-9 LSCAN | Airbag deployed Seat occupied detection telltale ON Airbag telltale ON Fasten seat belt signal ON Passenger's seat occupied telltale Airbag fault (diagnosis) | SDM | BCM CIM DIS IPC REC UEC |
| X1-8, X1-9 LSCAN | Airbag faulty display | IPC | SDM |
| X1-10 | Driver's airbag, looped through CIM contact unit | SDM | A24 |
| X1-11 | Driver's airbag, looped through CIM contact unit | SDM | A24 |
| X1-13 | Passenger's airbag | SDM | A62 |
| X1-14 | Passenger's airbag | SDM | A62 |
| X1-15 | Ignition ON (terminal 15), directly wired to CIM | CIM | SDM |
| X2-9 | Belt lock switch, driver's side – looped through DSM | SDM | Sxx |
| X2-10 | Belt lock switch, driver's side – looped through DSM | SDM | Sxx |
| X2-15 | The SDM communicates the occurrence of an accident via this line (Onstar function) | SDM | NAV CAR |
| X2-20 | Seat belt tensioner, driver – looped through DSM | SDM | Y128 |
| X2-21 | Seat belt tensioner, driver – looped through DSM | SDM | Y128 |
| X2-22 | Seat belt tensioner, passenger | SDM | Y129 |
| X2-23 | Seat belt tensioner, passenger | SDM | Y129 |
| X2-26 | Curtain airbag, driver | SDM | A96_L |
| X2-27 | Curtain airbag, driver | SDM | A96_L |
| X2-28 | Curtain airbag, passenger | SDM | A96_R |
| X2-29 | Curtain airbag, passenger | SDM | A96_R |
| X2-30 | Side airbag, driver – looped through DSM | SDM | A96_D |
| X2-31 | Side airbag, driver – looped through DSM | SDM | A96_D |
| X2-32 | Side airbag, passenger | SDM | A96_P |
| X2-33 | Side airbag, passenger | SDM | A96_P |
| X2-45 | Seat belt tensioner, rear left | SDM | Y127_L |
| X2-46 | Seat belt tensioner, rear left | SDM | Y127_L |
| X2-47 | Seat belt tensioner, rear right | SDM | Y127_R |
| X2-48 | Seat belt tensioner, rear right | SDM | Y127_R |
| X2-70 | Passenger's side airbag sensor | A66_L | SDM |
| X2-71 | Passenger's side airbag sensor | A66_L | SDM |
| X2-72 | Driver's side airbag sensor | A66_R | SDM |
| X2-73 | Driver's side airbag sensor | A66_R | SDM |
| X2-74 | Seat occupied detection sensor, passenger | A76 | SDM |
Functional Description
The airbag control unit is connected to the low-speed CAN bus. It receives the ignition key status from the CIM and transmits the airbag status to the BCM, CIM, DIS, IPC, REC, UEC for the telltales and displays. In the case of airbag deployment, if available, a message is transmitted to the NAV and CAR and an emergency call is effected via Onstar. The ignition circuits and the airbag function sensors feature conventional wiring, owing to the high speed requirements. They cannot be controlled via the CAN bus.
Fault Monitoring Function
A fault monitoring / fault diagnosis function is integrated in the control unit, which continuously monitors all the control unit inputs and outputs, as well as the crash sensors and restraint systems.
If a fault is recognised in the control unit, the control unit transmits the message "Airbag control unit fault lamp ON" to the instrument via the LSCAN. After receiving this message, the instrument actuates the airbag fault lamp.