Control Module

WARNING: This page is about a different car, the 2000 Volvo S80 and 1999 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.

Control module measures and records deceleration/collision force of vehicle to determine if air bag deployment is necessary. Control module also functions as a diagnostic monitor, which continuously monitors SRS operation and records any faults in SRS. Control module incorporates a piezoelectric sensor (to detect deceleration/collision force), microprocessors (to evaluate collision signal and control SRS deployment), a memory (to retain information for fault tracing if power supply fails) and a standby power unit (if battery power supply is lost).

To ensure correct operation of control module, it must be properly secured to floor and securely grounded. SRS is monitored continuously by microprocessors in control module, regardless of ignition switch position or engine operation. Control module will illuminate instrument gauge cluster SRS warning light until a fault is corrected, and control module memory is cleared.

Control module incorporates a standby power unit if normal power source (battery voltage) is interrupted. Standby power unit stores enough energy to deploy SRS within 10 seconds of battery power loss during a collision.