| Diagnosis and Testing Refer to Wiring Diagrams Section 501-20, for schematic and connector information. Special Tool(s) | | Simulator, Air Bag – Driver (Vehicles built up to 08/2002) 418-037 (40-001) | | | Simulator, Air Bag – Driver and Passenger (Vehicles built from 08/2002) 501-073 (40-016) | | | Simulator, Air Bag – Side and Safety Belt Buckle Pretensioner (Vehicles built up to 10/2001) 418-139 (40-011) | | | Simulator, Air Bag – Side and Safety Belt Buckle Pretensioner (Vehicles built from 10/2001) 501-093 (40-022) | | | Simulator, Air Bag – Passenger (Vehicles built up to 08/2002) 418-138 (40-010) | | | Test and Deployment Lead, Air Bag/Pyrotechnic Safety Belt 418-S055 (40-007A) | General Equipment Worldwide Diagnostic System (WDS) Diagnosing Customer Concerns Without Hard DTCs/LFCs WARNING:The battery back up power supply must be depleted before any work is carried out on the supplemental restraint system and adjacent components. Failure to follow this instruction may result in personal injury. NOTE:Following the pinpoint tests when a diagnostic trouble code/lamp fault code (DTC/LFC) is not present, will result in needless replacement of air bag system components and repeat repairs. Speak with the customer to determine if a particular set of conditions must be met in order to indicate a fault. If a LFC is reported by the customer but is not present when the vehicle comes in for repair, pinpoint test diagnostics cannot be used. Instruct the customer on how to count an LFC. Diagnosing Customer Concerns with Hard DTCs/LFCs WARNING:Do not use substitute air bag simulators when working on the supplemental restraint system. Use only the appropriate tool. Failure to follow these instructions may result in personal injury. Most air bag system diagnostic procedures require the use of system deactivation and system reactivation procedures. These procedures require the air bag module(s) and safety belt pretensioners to be disconnected from the SRS, thereby removing the risk of air bag deployment while diagnostics are carried out. Air bag simulators are required to carry out diagnosis and testing of the air bag system. It is not acceptable to short-circuit the air bag module connections with a 0 ohm jumper wire. If a 0 ohm jumper wire is used to short-circuit the air bag module connections, a LFC will be displayed and a DTC logged by the air bag control module. Deactivation WARNING:The back up power supply must be depleted, before any work is carried out on the supplemental restraint system. Wait at least one minute after disconnecting the battery ground cable. Failure to follow this instruction may result in personal injury. - Wait at least one minute for the backup power supply in the air bag control module to deplete its stored energy.
WARNING:Place the air bag module(s) on a ground wired bench, with the trim cover facing up. Failure to follow this instruction may result in personal injury. -
NOTE:Vehicles built up to 08/2002 install 418-037. Vehicles built from 08/2002 install 501-073. Connect the driver air bag simulator to the sub-harness in place of the driver air bag module at the top of the steering column. -
NOTE:Vehicles built up to 08/2002 install 418-138. Vehicles built from 08/2002 install 501-073. Connect the passenger air bag simulator to the harness in place of the passenger air bag module. - Disconnect the driver underseat floor harness electrical connector.
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NOTE:Vehicles built up to 10/2001 install 418-139. Vehicles built from 10/2001 install 501-093. Connect the air bag simulator to the driver underseat floor harness electrical connector in place of the safety belt pretensioner and side air bag module. - Disconnect the passenger underseat floor harness electrical connector.
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NOTE:Vehicles built up to 10/2001 install 418-139. Vehicles built from 10/2001 install 501-093. Connect the air bag simulator to the passenger underseat floor harness electrical connector in place of the safety belt pretensioner and side air bag. Reactivation WARNING:The air bag simulators must be removed and the air bag modules reconnected when reactivated to avoid non-deployment in a collision. Failure to follow this instruction may result in personal injury. - Wait at least one minute for the backup power supply in the air bag control module to deplete its stored energy.
- Remove the driver air bag simulator from the sub-harness at the top of the steering column.
- Remove the passenger air bag simulator from the passenger air bag module harness.
- Remove the air bag simulator from the driver underseat floor harness electrical connector.
- Connect the driver underseat floor harness electrical connector.
- Remove the air bag simulator from the passenger underseat floor harness electrical connector.
- Connect the passenger underseat floor harness electrical connector.
Glossary Air Bag Simulator Air bag simulators are used to simulate air bag module connections to the system. Deactivate the System Deactivate the system means to carry out the deactivation procedure. REFER to Deactivation in this section. Prove Out the System The air bag warning indicator will illuminate for approximately three seconds. If a fault is detected the indicator flashes a corresponding fault code. Reactivate the System Reactivate the system means to carry out the reactivation procedure. REFER to Reactivation in this section. Principles of Operation Supplemental Restraint System (SRS) Operation The vehicle is equipped with an AC fired sensing system. In the event of a severe frontal or three-quarter frontal impact, in excess of a predetermined limit the driver and passenger (if equipped) front air bag(s) will deploy. In the event of a severe full side impact, in excess of a predetermined limit either the driver or passenger side air bag (if equipped) will deploy. Air bag deployment will only occur, in the event of a severe collision when the ignition key is in the RUN position. Air Bag Control Module The air bag control module retains full control of the whole system, providing continual system checks and full diagnostic capabilities. The non-volatile memory stores the fault codes, which can then be downloaded through the data link connector (DLC) to WDS. In the event of a failure in the vehicle supply during an accident, the air bag control module provides an auxiliary power supply, sufficient to deploy the air bag(s) for a minimum of 150 mS. The back up power supply is discharged by the air bag control module within 60 seconds of the battery ground cable being disconnected. Thus making sure the supplemental restraint system remains operational. The air bag control module contains electronic acceleration sensor(s) which measure the longitudinal acceleration and the lateral acceleration (on vehicles equipped with side air bags) and provide both signals to the microcontroller proportional to the amount of acceleration measured. When both these sensors sense an impact in excess of a predetermined limit, the air bag control module initiates the circuit to deploy the air bags. The air bag control module also contains a safing sensor which enables the front air bags and the safety belt buckle pretensioners in the event of a front impact and only the safety belt buckle pretensioners in the event of a rear impact. The safing sensor also prevents unintentional deployment of the front air bags and safety belt buckle pretensioners in the event of a fault in the electronic acceleration sensor(s). On vehicles equipped with the telematics system, there is a link from the air bag control module to the telematics control module. In the event of an air bag deployment the telematics control module will automatically send an SOS call. REFER to Section 419-05 . Air Bag Control Module Configuration - Ground Connection (Vehicles built from 08/2002) The air bag wiring harness connections are the same for LHD and RHD. The air bag control module is internally configured as LHD or RHD. A ground connection on the configuration pin providing the signal to confirm the air bag control module as RHD. This ground connection is not present in LHD vehicles. The air bag control module continuously monitors for this ground signal and a DTC will be logged by the air bag control module for an incorrect condition. Front Crash Sensor (Vehicles built from 08/2002) The front crash sensor contains an acceleration sensor, filter, amplifier and an application specific integrated circuit for signal transmitting and is mounted on the hood latch panel. The front crash sensor sends a signal at a level determined by the crash severity to the air bag control module. The air bag control module will evaluate the signal against stored data and deploy the frontal air bags and safety belt buckle pretensioners if required. Side Impact Sensor The side impact sensors are mounted on to the seat crossmember on either side of the vehicle, to facilitate remote lateral impact sensing. Each side impact sensor contains a micromachine which processes signals from an accelerometer within the sensor. In the event of an impact, in excess of a predetermined limit, the side impact sensor will process the side impact data and initiate a deployment request to the air bag control module. The air bag control module processes this request against stored data, to deploy the side air bag on the side the deployment request was initiated. The air bag control module retains control of the side air bags. Air Bag Warning Indicator The air bag warning indicator is incorporated into the instrument cluster, together with the automatic detach detect (ADD) circuit. The air bag warning indicator illuminates for three seconds at key ON. If the system self-tests OK the indicator extinguishes, if a fault is detected the indicator flashes a corresponding fault code. The ADD circuit is designed to illuminate the air bag warning indicator continuously if the air bag control module circuit is broken, either by loss of power or ground supply. The air bag control module retaining bolts are part of the ground circuit. Diagnostic evaluation of the SRS can be made through the data link connector (DLC) and WDS to establish the nature of the concern. Once the DTC is known the appropriate course of action can be selected from the Symptom Chart.
REFER to Diagnostic Instructions - Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) in this section.
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