9J–4
SUPPLEMENTAL RESTRAINT SYSTEM
SRS Component and Wiring
Location View
810RX015
Legend
EndOFCallout
Component Description
SDM (Sensing and Diagnostic Module)
WARNING: DURING SERVICE PROCEDURES, BE
VERY CAREFUL WHEN HANDLING A SDM. NEVER
STRIKE OR JAR THE SDM. NEVER POWER UP THE
SRS WHEN THE SDM IS NOT RIGIDLY ATTACHED
TO THE VEHICLE. ALL SDM AND MOUNTING
BRACKET FASTENERS MUST BE CAREFULLY
TORQUED AND THE ARROW MUST BE POINTED
TOWARD THE FRONT OF THE VEHICLE TO
ENSURE PROPER OPERATION OF THE SRS. THE
SDM COULD BE ACTIVATED WHEN POWERED
WHILE NOT RIGIDLY ATTACHED TO THE VEHICLE
WHICH COULD CAUSE DEPLOYMENT AND RESULT
IN PERSONAL INJURY.
The SDM is designed to perform the following functions
in the Supplemental Restraint System (SRS):
1. Energy Reserve — The SDM maintains 24–Volt
Loop Reserve (24VLR) energy supply to provide
deployment energy when ignition voltage is lost in a
frontal crash.
2. Frontal Crash Detection — The SDM monitors
vehicle velocity changes to detect frontal crashes
which are severe enough to warrant deployment.
3. Air Bag Deployment — When a frontal crash of
sufficient force is detected, the SDM will cause
enough current to flow through the air bag assembly
to deploy the air bag.
4. Malfunction Detection — The SDM performs
diagnostic monitoring of SRS electrical components
and sets a diagnostic trouble code when a
malfunction is detected.
5. Frontal Crash Recording — The SDM records
information regarding SRS status during frontal
crash.
6. Malfunction Diagnosis — The SDM displays SRS
diagnostic trouble codes and system status
information through the use of a scan tool.
7. Driver Notification — The SDM warns the vehicle
driver of SRS malfunctions by controlling the “Air
Bag" warning lamp.
The SDM is connected to the SRS wiring harness by a
24–pin connector. This harness connector uses a
shorting clip across certain terminals in the contact
area. This shorting clip connects the “AIR BAG"
warning lamp to ground when the SDM harness
connector is disconnected or Connector Position
Assurance (CPA) is not inserted even if completely
connected. This will cause the “AIR BAG" warning
lamp to come “ON" steady whenever the ignition switch
is at the ON or START positions with the SDM
disconnected.
(1) Battery
(2) Relay & Fuse Box
(3) SRS Coil Assembly
(4) Driver Air Bag Assembly
(5) Meter Assembly
(6) Passenger Air Bag Assembly
(7) SDM
(8) Starter Switch
(9) Fuse Box, SRS, METER