You can find Maruti Suzuki ECM / ECU in engine compartment near the battery. It is bolted to the chassis with four bolts. Always remove the battery first before opening the ECM as sparking and voltage fluctuation can damage the ECU.
You can find this port near driver door. It is usually covered in a Black colour plastic cap to protect it from dust & water so it may be hard to find. You need to remove this cap to reveal the OBD port. This port provides connectivity to car's computer ECM required for finding and analysing faults in car. Key programming is also possible through this OBD port.
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