88C-13
MR-413-X44-88C000$154.mif
V3
MRSZ AIRBAG
Vdiag: 04AIRBAGS AND PRETENSIONERS
Fault finding - List and location of components88C
1 - "Airbag Off" warning light:
The "airbag off" warning light is representative of the passenger airbag and passenger chest airbag inhibition status
if fitted.
–"off" = passenger airbag (switch on "ON") and passenger chest airbag (if fitted) active,
–"on" = passenger airbag (switch on "OFF" or fault detected on the switch line) and passenger chest
airbag (if fitted) inactive.
The "Airbag Fault" warning light comes on under the following conditions:
–detection and registering of an airbag system fault,
–a crash has been detected and registered,
–the computer is "crash locked" by the diagnostic tool,
–the computer must be programmed or reprogrammed.
2 - Passenger airbag inhibitor:
The passenger airbag inhibitor (by key) informs the airbag computer of a request to inhibit the passenger front airbag
and passenger chest airbag, if fitted.
3 - Driver's seat belt buckle sensor:
The seat belt buckle sensor gives the airbag computer the signal of whether the driver's belt is fastened or not.
4 - The driver and passenger buckle pyrotechnic pretensioners:
The buckle pyrotechnic pretensioner is integrated into the front seat belt buckle.
The pretensioner holds the occupant in the seat in the event of a crash.
5 - The driver and passenger rear seat belt pyrotechnic retractors:
The rear seat belt pyrotechnic retractor is integrated into the rear seat belt inertia reel.
The pyrotechnic seat belt retractor holds the occupant in the seat in the event of a crash.
88C-16
MR-413-X44-88C000$308.mif
V3
88C
AIRBAGS AND PRETENSIONERS
Fault finding - Function
The MRSZ airbag computer takes control of all of the vehicle's restraint devices intended to ensure the protection of
the occupants (driver, front and rear passengers).
The MRSZ computer is designed to carry out the following functions:
●detection and confirmation of longitudinal impacts (front or rear) and/or side impacts,
●corresponding activation of the pyrotechnic restraint devices (e.g.: pretensioner, airbag),
●management of the different signals relating to the characteristics of the occupants (e.g.: presence detection),
●management of the function inhibiting the trigger lines and the passenger sensor,
●management and surveillance of the instrument panel "Airbag Fault" and "Airbag Off" warning lights via the
CAN network,
●activation of the "Crash output" signal via the CAN in the event of a crash,
●management of the fault finding signals (signals provided by the fault manager in response to fault finding
requests, whether this consists of internal faults or input/output fault finding).
Special notes:
–Frontal impacts:
This function is carried out using the MRSZ accelerometer. Accelerometers measure the violence of the impact. The
vehicle speed, the position of the passenger airbag locking switch and the accelerometer measurements determine
the strategy that the computer adopts to trigger the ignition modules. The front seat belt buckle pretensioners and
the front airbag may also be triggered or not depending on the input parameters.
–Side impacts:
This function is carried out by the MRSZ computer and the side impact sensors, if fitted.
The position of the passenger airbag locking switch and the accelerometer measurements determine the strategy
that the computer adopts to trigger the ignition modules. The front buckle pretensioners and the front chest-level
airbags and curtain airbags may also be triggered or not.
–Inhibition of passenger trigger lines:
This function is managed by the airbag computer, according to the position of the passenger airbag inhibition switch
and depending on the vehicle context.
The change in status of the inhibition switch must be done outside of after ignition feed. A change in status of the
switch is, however, authorised for 10 seconds after the after ignition feed for the vehicle is switched on.
If a change is status occurs outside of this 10 seconds, the computer will register a fault.
Inhibition programming:
–Trigger lines inhibited and "Airbag Off" warning light lit if switch is on "OFF" 100 Ω.
–Trigger lines authorised if the switch is on "ON" 400 Ω.
–Trigger lines inhibited, "Airbag Fault" and "Airbag Off" warning lights lit if a fault is detected, if the switch is not
configured and detected as present, or if there is a change of position outside of the conditions
MR-413-X44-88C000$308.mif
MRSZ AIRBAG
Vdiag: 04
88C-17
MR-413-X44-88C000$308.mif
V3
MRSZ AIRBAG
Vdiag: 04AIRBAGS AND PRETENSIONERS
Fault finding - Function88C
By default, when the key is in the inhibition position, the following protections and signals are inhibited in the event of
a crash:
–Passenger front air bag.
–Passenger chest-level airbag, if fitted.
The passenger front airbag and passenger chest-level airbag are inhibited when the locking switch is
positioned on OFF or when DF028 "PASSENGER AIRBAG STATUS INDICATOR LIGHT CIRCUIT" or DF193
"PASSENGER AIRBAG LOCKING STATUS CHANGE" is present in the computer memory.
–Seat belt locking monitoring:
This function is carried out by the instrument panel (seat belt reminder indicator light and buzzer). The MRSZ
computer only sends the driver's seat belt buckle sensor status.
An instrument panel warning light indicates that the seat belt is not being worn by the driver and a beep sounds as a
reminder when the vehicle speed exceeds 12 mph (20 km/h).
–Monitoring the information displayed on the instrument panel:
The instrument panel controls the correct operation of the "Airbag fault" and "Airbag OFF" warning lights and
informs the airbag computer, via the multiplex network, of any possible malfunctions in the warning light circuits.
