SAFARI

19 AIR BAGS SRS 11. DIAGNOSTICS FOR AIR BAG (ORS) SYSTEM 1. General Air Bag ECU is used for controlling firing of air-bags for passenger safety on Safari in event of a crash. This air bag module has a provision for sensing the front impacts. The system includes the possibilities to handle front air bags (driver and passenger) and seat pretensioners for driver and passenger.The unit is equipped with 4 squib line configuration inputs and one main warning lamp output. The Micro controller inside the ECU ,evaluates continuously the signal from the accelerometer sensor. Based on the analog signal the crash algorithm will decide whether or not to fire the air bag system and restraint system. During the ignition (start up) of the vehicle ,the system will make number of self tests and the functionality will be indicated by the warning lamp which is placed in the instrument cluster. The ECU has a standard interface based on Key word 2000 protocol for diagnostics . The interface allows checking Electrical connections , resetting errors and reading the crash data . Electronics division has developed a diagnostic unit which handles these functions and provides a user friendly interface based on laptop PC andWindows. 1.1 Salient Features This diagnostic unit is capable of performing the following functions 1. With the diagnostic unit the squib configuration Serial RS232 COM Port i.e. PAB or DAB ( passenger or driver air bag ) can be read from the ECU. 2. The vehicle identification number (VIN) can be entered into the ECU by diagnostic unit .This no is to identify the vehicle onto which the ECU is fitted. 3. The different diagnostic trouble (errors) codes like accelerometer error, sensors error, warning lamp error, battery voltage error etc, can be read from the ECU and corrective action can be taken accordingly. 4. Diagnostic unit will also provide ECU information like the vehicle identification number, squib configuration(i.e. with or without passenger air bag),type of vehicle etc. 5. Diagnostic unit also provides the crash data like the crash time, velocity value, energy value, temperature at the time of crash etc for analysis. 2 Detailed Description Required power supply : Power supply for the Laptop/Desktop TheVehicle Interface Unit does not require any external power supply. It works on vehicle battery, provided through the OBD cable. Connect the RS232 cable to the Laptop/Desktop COM port The OBD cable is connected to the Diagnostic connector of the wiring harness. PC/Laptop (with software) Vehicle Interface Unit OBD cable Airbag diagnostic connection block diagram. ToAirbagdiagnostic connector below co-driver seat