Occupant Restraint Controller

Occupant Restraint Controller (ORC) is located under center of floor console. It contains a microprocessor, an impact sensor and an energy storage capacitor. The microprocessor contains air bag system logic. Air bag system logic includes On-Board Diagnostics (OBD) capability. ORC communicates with other modules via the Programmable Communication Interface (PCI) bus circuit.

ORC microprocessor monitors impact sensor signal and air bag system electrical circuits to determine system readiness. If ORC detects a monitored system fault, a message is sent via PCI bus circuit to Electro-Mechanical Instrument Panel (EMIC) module to turn air bag indicator light on. ORC is preprogrammed to determine when deceleration rate signaled by impact sensor indicates an impact severe enough to require air bag system protection. When preprogrammed conditions are met, ORC sends a signal to deploy air bag system components.

The impact sensor is an accelerometer that senses the rate of vehicle deceleration, which provides verification of direction and severity of an impact. Impact sensor is calibrated for specific vehicle, and is only serviced as an integral part of ORC. ORC energy storage capacitor provides air bag system protection in severe secondary impact if initial impact has damaged or disconnected vehicle battery, but initial impact is not severe enough to deploy air bags.

EMIC module performs air bag indicator light check when ignition switch is turned to RUN or START position. EMIC module turns indicator light on for 6-8 seconds. Light turns off if ORC determines no system malfunctions exist. Light remains on if ORC determines an air bag system malfunction or if EMIC light circuit short to ground exists. If light turns on for more than 8 seconds and then goes off, an intermittent problem in air bag system is indicated. For additional information on air bag system, see AIR BAG RESTRAINT SYSTEMS - CARS article.