Contents Wiring diagrams Section: Restraints Control Systems All sections

SRS Airbag Control System: Overview Nissan Versa II

Restraints Control Systems 3 illustrations ~489 words

Component Description

ComponentFunction
Air bag diagnosis sensor unitRefer to " AIR BAG DIAGNOSIS SENSOR UNIT ".
Driver air bag moduleRefer to " DRIVER AIR BAG MODULE ".
Front passenger air bag moduleRefer to " FRONT PASSENGER AIR BAG MODULE ".
Front side air bag moduleRefer to " FRONT SIDE AIR BAG MODULE ".
Side curtain air bag moduleRefer to " SIDE CURTAIN AIR BAG MODULE ".
Front seat belt pre-tensionerRefer to " FRONT SEAT BELT PRE-TENSIONER ".
Occupant classification systemRefer to " OCCUPANT CLASSIFICATION SYSTEM: SYSTEM DESCRIPTION ".
Crash zone sensorRefer to " CRASH ZONE SENSOR ".
Side air bag (satellite) sensorRefer to " SIDE AIR BAG SATELLITE SENSOR ".
Front door (satellite) sensorRefer to " DOOR SATELLITE SENSOR ".
Seat belt buckle switchThe seat belt buckle switches (LH/RH) provide the seat belt buckle signals to the air bag diagnosis sensor unit and the combination meter.
Spiral cableThe spiral cable provides a rotating physical connection to the driver air bag module.
Combination meterThe combination meter displays the air bag warning lamp and the seat belt warning lamp. The air bag warning lamp is used for diagnosis in User Mode and may be used to display diagnostic trouble codes without the use of the CONSULT.

SRS AIR BAG SYSTEM: System Description

  1. The air bag deploys if the air bag diagnosis sensor unit is activated while the ignition switch is in the ON or START position.
  2. The collision modes for which supplemental restraint systems are activated are different among the SRS systems. For example, the driver air bag module, front passenger air bag module and front seat belt pre-tensioners are activated in a frontal collision but not in a side collision.

OCCUPANT CLASSIFICATION SYSTEM: System Description

The occupant classification system (OCS) identifies different size occupants, out of position occupants, and detects if child seat is present in the front passenger seat. The OCS control unit (2) receives inputs from the occupant classification sensors (1) (located inside the passenger seat cushion assembly). Depending on classification of the passenger, the OCS sends a signal to the air bag diagnosis sensor unit. The air bag diagnosis sensor unit uses this signal and the seat belt buckle switch RH signal to determine deployment or non deployment of the passenger front air bag in the event of a collision. Depending on the signals received, the air bag diagnosis sensor unit can disable the passenger front air bag completely. The OCS (weight sensors) must be set to zero point using CONSULT after servicing the OCS system.

Note. CONSULT can be used to confirm when "zero point reset" for OCS is complete. Always perform zero point reset after the removal and installation of the seat or when disconnecting the OCS control unit harness connector even if zero point reset has been completed in the past. If zero point reset is incomplete, the passenger air bag will be disabled and the passenger air bag off indicator will be ON. In case of customer concern, CONSULT can be used to confirm the passenger air bag status (readiness).

Front Passenger Seat (Condition)PASS AIR BAG OFF Indicator (Status)Passenger Air Bag Status (Readiness)CONSULT Display
Seat occupiedOFFActive (enabled)ON
Seat occupied (1)ONDeactivated (disabled)OFF
Seat emptyOFFDeactivated (disabled)OFF
NOTE: (1) Passenger does not meet Occupant Classification System specifications for passenger air bag activation.
NOTE
(1) Passenger does not meet Occupant Classification System specifications for passenger air bag activation.
(1)Passenger does not meet Occupant Classification System specifications for passenger air bag activation.

PASSENGER AIR BAG STATUS CONDITIONS

Scheme 1

Scheme 1

Scheme 2

Scheme 2: SEAT BELT WARNING LAMP SYSTEM: System Diagram

SEAT BELT WARNING LAMP SYSTEM: System Description

The seat belt warning lamp (1) will remind the driver if the driver or front passenger seat belt should be buckled. The system works in conjunction with the occupant classification system. Refer to " OCCUPANT CLASSIFICATION SYSTEM: SYSTEM DESCRIPTION ".

Scheme 3

Scheme 3: SEAT BELT WARNING LAMP SYSTEM: System Description
Driver seat status (Ignition switch ON)Passenger seat statusSeat belt buckle switch LH statusSeat belt buckle switch RH statusSeat belt warning lamp
Seat occupiedSeat occupiedBuckledBuckledOff
UnbuckledOn
Seat unoccupiedOff
UnbuckledOn

SEAT BELT WARNING SYSTEM OPERATION

Diagnosis Description

CAUTIONDo not use electrical test equipment on any circuit related to the SRS unless instructed to do so in this Service Information. SRS wiring harnesses can be identified by yellow and/or orange harness connectors. Do not attempt to repair, splice or modify SRS wiring harnesses. If a harness is damaged, replace it with a new one. Keep ground connections clean.

ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT: Description

Always perform zero point reset using CONSULT when removing and installing the passenger seat or servicing the occupant classification system.

ZERO POINT RESET: Description

Zero point reset is an initializing procedure for the OCS (weight) sensors that must be performed using CONSULT when removing and installing passenger seat or servicing the OCS system. If zero point reset is not performed, the initialization is incomplete and OCS may not operate normally.

Note. When reinstalling the passenger seat, the initial value for the OCS sensors may change, and the OCS may not operate normally. When zero point reset is performed after removal and installation of passenger seat, CONSULT displays ""complete"".