Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Air Bag Supplemental Restraint System (SRS)
Restraint System Diagnostic Tool Warning
WARNING: Restraint system diagnostic tools are for service only. Tools must be removed prior to operating the vehicle over the road. Failure to remove restraint system diagnostic tools could result in injury and possible violation of vehicle safety standards.
Diagnosing Customer Concerns Without Hard DTCs
If a lamp fault code (LFC) is reported by the customer but is not present when the vehicle comes in for service, follow the Diagnostic Instruction procedures in this section to identify the intermittent DTC.
Once the DTC is known, read the Normal Operation section of the pinpoint test for the DTC involved.
Follow the deactivation or depowering procedure as directed in this section.
Determine the location of components involved in creating the DTC.
Carry out a thorough visual inspection of:
splices and wiring harnesses.
insulation on conductors.
Refer to the Possible Causes section of the pinpoint test for the DTC involved, which lists the common concerns that relate to the DTC. Concerns are listed according to priority.
Diagnosing Customer Concerns with Hard DTCs
Most Supplemental Restraint System (SRS) diagnostic procedures will require deactivation and reactivation or depowering and repowering of the system. Deactivation and reactivation requires the disconnection of most SRS components and the installation of restraint system diagnostic tools. Depowering and repowering requires disconnecting of the battery and removal of the electronic crash sensor (ECS) module fuse. This reduces the risk of inadvertent deployment of SRS components while diagnostic procedures are being carried out.
Restraint system diagnostic tools are required for the diagnosis and testing of the SRS. It is not acceptable to short-circuit the air bag module connections with a jumper wire. If a jumper wire is used to short-circuit the air bag module connections, a lamp fault code (LFC) will be displayed.
Prove Out Procedure
Turn the ignition switch from the OFF to the ON position and visually monitor the air bag indicator with all SRS components connected or restraint system diagnostic tools installed. The air bag indicator will light continuously for approximately six seconds and then turn off. If an SRS fault is present, the air bag indicator will either:
fail to light.
remain lit continuously.
The flashing might not occur until approximately 30 seconds after the ignition switch has been turned from the OFF to the ON position. This is the time required for the electronic crash sensor (ECS) module to complete the testing of the SRS. If the air bag indicator is inoperative and an SRS fault exists, a chime will sound in a pattern of five sets of five beeps. If this occurs, the air bag indicator will need to be repaired before diagnosis can continue.
The secondary air bag warning is an audible fault format that consists of five sets of five tone bursts, with each set of five tone bursts separated by a five second quiet period. One tone burst cycle will consist of one second ON and one second OFF. This series of five activations is repeated every 30 minutes.
Air Bag/Pretensioner Restraint System Diagnostic Tools
Air bag/pretensioner restraint system diagnostic tools are used to simulate the equivalent resistance of an air bag module or safety belt pretensioner during certain diagnostic procedures.
Disconnect the Component
Disconnect the component means to disconnect the component vehicle harness connector, not to remove the component. Do not reconnect a disconnected component unless instructed to do so.
Prove out the system means to turn the ignition switch from the OFF to the ON position, and to visually monitor the air bag indicator with the air bag modules and safety belt pretensioners or restraint system diagnostic tools installed. For additional information, refer to Prove Out Procedure in this section.
The checklist below should be completed following diagnosis or repair of any air bag system concern:
All restraint system diagnostic tools removed?
Driver air bag connector at base of steering column connected?
All air bag modules connected?
air bag electronic crash sensor (ECS) module connected?