Air Bags - System Diagnostics: Overview
Group: ELECTRICALNumber: 99-90-009
Date: JULY, 1999
Model: ALL 1999
Subject
AIR BAG SYSTEM DIAGNOSTICS
DESCRIPTION:
This TSB gives general instructions for diagnosing the Supplemental Restraint System (SRS), also known as the Air Bag System.
GENERAL INFORMATION
The following acronyms and terms are commonly used in the air bag system:
^ DAB Driver Air Bag, the one in the steering wheel
^ PAB Passenger Air Bag, the one in the dash in front of the passenger seat
^ DSAB Driver Side Air Bag, the one in the left front seat
^ PSAB Passenger Side Air Bag, the one in the right front seat
^ DSBPT Driver Seat Belt Pretensioner
^ PSBPT Passenger Seat Belt Pretensioner
^ PPD Passenger Presence Detector
^ Squib The part of the airbag or pretensioner where the wire harness plugs into the firing circuit in the airbag/pretensioner.
^ SRSCM Supplemental Restraint System Control Module
^ Shorting Bar "Shorting Bars" are spring-loaded contacts which purposely short the air bag or pretensioners contacts together when the SRSCM connector is removed.
NOTE:
Clock Spring and wire harness not shown.
GENERAL SAFETY PRECAUTIONS:
The following are general safety rules for working on a vehicle equipped with an Air Bag System. Be sure to review the specific safety instructions in the correct shop manual for the vehicle being serviced.
1. Before performing service on any component in the Air Bag System, turn the ignition key off and disconnect the negative battery terminal. Wait at least 30 seconds for the back-up power in the SRSCM to dissipate before resuming work.
2. Always use new parts for replacement. (Never use air bag parts from another vehicle.)
3. Never attempt to disassemble the parts from an air bag system.
4. If any air bag system component has been dropped, or if there are any cracks, dents, or other visible defects, replace that component with a new one.
5. Disconnect the negative battery terminal before performing any welding on the vehicle.
6. Do not make any sharp blows or impacts on the vehicle, especially near the SRSCM or the satellite sensors, until after the battery negative terminal has been disconnected.
7. After completing the diagnosis and repair, always check for SRS codes generated during the repair of the system. Verify there are no new codes indicating items requiring service, then clear them.