ZEST BOLT Service Manual

SRS 4 10.2.4 SRS ECU The SRS ECU gets power supply from vehicle battery and is designed to perform the following functions in the air bag system:  Energy Reserve: SRS ECU maintains a Reserve energy supply to provide deployment energy after ignition voltage is lost during frontal crash.  Frontal and Side Crash Detection: SRS ECU monitors vehicle deceleration levels to detect frontal and side crashes which are severe enough to warrant deployment.  Air Bag Deployment: When a frontal or side crash of sufficient severity is detected, the SRS ECU will cause enough cur- rent to flow through the air bag (inflator) modules to deploy the air bags.  Malfunction Detection: The SRS ECU performs diagnostic monitoring of the air bag system electrical components and switches on the indication on instrument cluster and sets a diagnostic trouble code when a mal- function is detected.  Malfunction Diagnosis: SRS ECU displays air bag diagnostic trouble codes and system status information through the use of diagnostic tool.  “SRS” Warning Lamp Control: The light is turned ON to warn the driver of occurrence of a fault and it also comes on as soon as ignition supply is switched on to check proper functioning of “AIR BAG” warning lamp.  Interface with Passenger airbag activation switch: The ECU disables the passenger airbag when the passenger airbag inhibition switch is turned to OFF position and displays the condition on the fascia switch panel.