New software for the supplemental restraint system module (SRS) can be downloaded. When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK, the software is downloaded to the control module.

If the comparison between the vehicle and Volvo central database is not OK, software downloading cannot occur.

When the control module is replaced, the new control module will have certain pre-programmed software.

The software which is pre-programmed is

application software
diagnostic software
collision algorithm software.

The software which will be downloaded is parameter files containing

parameters unique to this model
equipment for the vehicle (passenger air bag, adaptive seatbelt force limiter etc.)
a signal configuration file.

Scheme 192

Scheme 192: CHECKING THE 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)
side impact sensors (7/115, 7/116, 7/208 and 7/209)
door mounted inflatable curtains (8/66 and 8/67)
SIPS bags (8/51 and 8/52)
frontal impact sensor (7/178 and 7/179)
front seat belt buckles (3/93 and 3/94)
adaptive steering column (8/99) (USA/CDN only)
seat position sensors (3/255 and 3/256) (USA/CDN only)
adaptive seatbelt force limiter (8/128 and 8/129) (USA/CDN only)
switch on/off, front passenger airbag (3/157) (not USA/CDN)
occupant weight sensor (OWS) (7/93) (USA/CDN only)
roll-over bar cassette (8/57 and 8/58).

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 lamp lights and a warning text is displayed in the driver information module (DIM).
the general yellow warning lamp lights and a warning text is displayed in the driver information module (DIM).

The driver information module (DIM) continuously transmits a signal to the supplemental restraint system module (SRS) via the controller area network (CAN) with information about whether the SRS indicator lamp is working or not. The red general warning lamp lights up if the SRS indicator lamp stops working. If the CAN communication between the supplemental restraint system (SRS) module and the driver information module (DIM) fails, the SRS warning lamp lights up and text is displayed in the driver information module (DIM). If the faults disappear and the driver information module (DIM) can transmit information to the supplemental restraint system module (SRS) and the status of the SRS warning lamp is OK, the warning lamps will return to normal function.

Scheme 193

Scheme 193: SIDE IMPACT

In the event of a side-on collision, the sensors in the Supplemental restraint system module (SRS) (4/9) and the side impact sensors (7/115, 7/116, 7/208 and 7/209) evaluate the force of the mechanical stresses. The Supplemental restraint system module (SRS) determines which protection system is to be activated in the situation.

If the impact fulfils the conditions to activate the side airbags (8/51 and 8/52) and the door mounted inflatable curtains (8/66 and 8/67) and/or seat belt tensioners front (8/33 and 8/34), the control module sends a current pulse to those protection systems that are to be deployed. The side impact protection system will only be deployed on the side where the impact is registered.

The control module also transmits a collision signal on a directly connected cable to the central electronic module (CEM) (4/56) and the phone module (PHM) (16/60), so that these control modules can take certain actions.

A collision status signal is also sent to the phone module (PHM) and the central electronic module (CEM) via the controller area network (CAN).

Scheme 194

Scheme 194: FRONTAL COLLISION

In the event of a frontal collision, the sensors in the Supplemental restraint system module (SRS) (4/9) and frontal impact sensors (7/178 and 7/179) evaluate the mechanical stresses. The Supplemental restraint system module (SRS) determines which protection system is to be activated in the situation.

If the impact fulfils the conditions to activate the protection system the Supplemental restraint system module (SRS) sends an activation signal, a current pulse, to

front airbags (8/30, 8/31, 8/32 and 8/61) and/or
seat belt tensioner (8/33, 8/34, 8/55 and 8/56) and/or
the adaptive steering column (8/99) and/or
the function for adaptive seatbelt force limiting.

The passenger airbag will not be deployed if it is deactivated using the Occupant weight sensor (OWS) (7/93).

A collision signal is transmitted on a direct connection from the supplemental restraint system module (SRS) to the central electronic module (CEM) (4/56) and phone module (PHM) (16/60) when the collision protection system is activated. These two control modules ensure that

switch off the fuel pump (FP)
switch off the engine cooling fan (FC)
switch off the windshield wipers when the car is stationary
switch on the interior lighting and the courtesy lighting
set the vehicle to collision status
unlock the central locking system and
if the vehicle is equipped with Volvo On Call (Plus), send an automatic alarm to CSC (Customer Service Center).

Scheme 195

Scheme 195: ROLL OVER

In the event of a roll over, the sensors, mounted in the Supplemental restraint system module (SRS) (4/9), evaluate the angle of the vehicle and how quickly the vehicle angle will change. When the movement has exceeded the predetermined limit, the following components are activated

door mounted inflatable curtains (8/66 and 8/67)
seat belt tensioners (8/33, 8/34, 8/55 and 8/56)
roll-over bar cassettes (8/57 and 8/58).

switch off the fuel pump (FP)
switch off the engine cooling fan (FC)
switch off the windshield wipers when the car is stationary
switch on the interior lighting and the courtesy lighting
set the vehicle to collision status
unlock the central locking system and
if the vehicle is equipped with Volvo On Call (Plus), send an automatic alarm to CSC (Customer Service Center).

Scheme 196

Scheme 196: FUNCTION FOR ADAPTIVE SEATBELT FORCE LIMITATION

In the event of a frontal collision where the front airbags and the front seat belt tensioners have deployed (8/33 and 8/34), the function for adaptive seatbelt force limiting may be activated. The supplemental restraint system module (SRS) also receives information from the seat position sensor (3/255, 3/256) about the positions of the passenger or driver's seats. The control module can determine whether the occupant is a large or small person. Using this information, the supplemental restraint system module (SRS) determines whether the adaptive seatbelt force limiter should be activated. If the adaptive seatbelt force limiter (8/128, 8/129) is activated, the supplemental restraint system module (SRS) transmits an activation signal, current pulse, to the adaptive seatbelt force limiter which reduces the force of the seatbelt on the chest.

Scheme 197

Scheme 197: ACTIVATING/DEACTIVATING FRONT PASSENGER AIRBAG

Under normal conditions the information from the occupant weight sensor (OWS) system (7/93) is the basis for whether the supplemental restraint system module (SRS) (4/9) should activate or deactivate the front passenger airbag (8/31 and 8/32). The occupant weight sensor (OWS) communicates continuously with the supplemental restraint system (SRS) module via the local controller area network (CAN). When a passenger weighing more than a certain weight is in the seat, the supplemental restraint system module (SRS) is informed by the occupant weight sensor (OWS). The control module software activates the front passenger airbag, which means that the airbag has full functionality in the event of a collision. At the same time the supplemental restraint system module (SRS) transmits a signal on the controller area network (CAN), to the central electronic module (CEM) (4/56), with a request to switch off the passenger airbag disconnected warning lamp. The central electronic module (CEM) then switches off the passenger airbag disconnected (PAD) warning lamp.

If the weight on the front passenger seat is below a certain level the supplemental restraint system module (SRS) is informed by the occupant weight sensor (OWS). The control module software deactivates the front passenger airbag, which means that the airbag has no functionality in the event of a collision. At the same time the supplemental restraint system module (SRS) transmits a signal on the controller area network (CAN), to the central electronic module (CEM), with a request to switch on the passenger airbag warning lamp (passenger airbag disconnected). The central electronic module (CEM) then switches on the passenger airbag warning lamp (passenger airbag disconnected). However there is an exception to this

The passenger airbag disconnected warning lamp will remain unlit if the occupant weight sensor (OWS) registers that the passenger seat is unoccupied. This means that the passenger airbag is deactivated.

Note. The on/off switch for the front passenger airbag and occupant weight sensor (OWS) must not be installed in the vehicle together.

FAULT INDICATION Volvo C70 II