Volvo 740 1989 Owner's Maintenance Manual page 40

1989 Volvo 740
A self-diagnostic system incorporated in the sensor monitors the SRS. If a fault is detected, the "SRS"
warning light will illuminate. The light is included in the warning/indicator light cluster in the
instrument panel. Normally, the SRS warning light will be illuminated along with the other warning/
indicator lights when the ignition key is turned to the ON position (position II), and go out after the
engine has been started. Check that this light is functioning properly every time the car is started.
The following items are monitored by the diagnostic system:
Sensor unit electronics integrity
Reserve energy supply
Diagnostic output service
System voltage
Integrity of system connectors
Mercury switch closure
Gas generator ignitor
WARNING!
If the SRS warning light stays on after the engine has started, or if it comes on while you are driving,
drive the car to the nearest authorized Volvo Dealer for inspection as soon as possible.
There is no maintenance to perform on the SRS yourself. The only periodic maintenance recommended
on the SRS is that the air bag module and the sensor unit should be replaced every ten years and that the
other components in the system (wiring, connectors, etc.) should also be inspected at this time. This
service must be performed by an authorized Volvo dealer.
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