SAFARI

AIR BAGS

SRS

11. DIAGNOSTICS FOR AIR BAG (ORS) SYSTEM

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

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.

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.

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.

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.

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