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.
