Checking SRS System
When the ignition key is turned from 0 to I, II or III, the communication on the controller area network (CAN), the status of the internal functions in the supplemental restraint system module (SRS) (4/9) as well as all directly connected components are checked:
- airbags driver (8/30 and 8/61)
- airbags passenger (8/31 and 8/32)
- seat belt tensioners (8/33, 8/34, 8/55 and 8/56)
- seat belt tensioners lap driver (8/92) (only certain markets)
- side impact sensors B-post (7/115 and 7/116)
- side impact sensors C-post (7/108 and 7/109)
- side impact sensors (7/108, 7/109, 7/115 and 7/116)
- inflatable curtains (8/66 and 8/67)
- SIPS bags (8/51 and 8/52)
- front impact sensors (7/178 and 7/179)
- front seat belt buckles (3/93 and 3/94)
- adaptive steering column (8/99) (only USA/CDN)
- seat position sensor (3/255 and 3/256) (only USA/CDN)
- adaptive seat belt force limiter (8/128 and 8/129) (only USA/CDN)
- seat belt roller sensor (7/194 and 7/195) (only USA/CDN)
- switch on/off, front passenger airbag (3/157) (not USA/CDN)
- occupant weight sensor (OWS) (7/93) (only USA/CDN)
The supplemental restraint system module (SRS) transmits information via the controller area network (CAN) to the driver information module (DIM) (5/1) indicating that this test is in progress. The central electronic module (CEM) (4/56) also transmits the parameter values during the status check.
The driver information module (DIM) then lights the SRS indicator lamp. The SRS indicator lamp is lit while the supplemental restraint system (SRS) is being checked. When the supplemental restraint system (SRS) has been tested and no faults have been detected, the SRS indicator lamp goes out.
If a fault is detected during the check it will be indicated in one of the following ways, depending on how serious it is:
- the SRS indicator lamp continues to light and a warning text is displayed in the driver information module (DIM)
- the general red warning light lights and a warning text is displayed in the driver information module (DIM).
- the yellow information light lights and a warning text is displayed in the driver information module (DIM).
The driver information module (DIM) continuously sends a signal via the CAN-network to the Supplemental restraint system module (SRS) with information about if the SRS-warning light is working or not. If the SRS-warning light stops working, the general red warning light is activated. If the CAN-communication between the Supplemental restraint system module (SRS) and Driver information module (DIM) stops, the general red warning light is activated and an associated warning text is shown on the display in the Driver information module (DIM). If the malfunctions disappear and the Driver information module (DIM) can send information again to the Supplemental restraint system module (SRS), and the status of the SRS-warning light is OK, the warning lights will return to normal function.