The air bag system used on the Celica is referred to as the Supplemental Restraint System (SRS). The SRS provides additional protection for the driver, if a forward collision of sufficient force is encountered. The SRS assists the normal seat belt restraining system by deploying an air bag.
The center air bag sensor is the heart of the SRS. It consists of safing sensors, inflator ignition control, diagnosis circuit, etc. The center air bag receives signals from the air bag sensors and determines whether the air bag must be activated or not. The center air bag sensor is also used to diagnose system malfunctions.
The air bag warning light circuit is equipped with an electrical connection check mechanism that detects when the connector to the center air bag sensor assembly is not properly connected.
All connectors in the air bag system are colored yellow. These connectors use gold-plated terminals with twin-lock mechanism. This design assures positive locking.
When the ignition switch is turned to the on or ACC positions, the air bag warning lamp will turn on for approximately 6 seconds. If no malfunctions are detected in the system after the 6 second period has elapsed, the warning light will go off.
The safing sensors are designed to go on at a lower deceleration rate than the front or center air bag sensor. When the vehicle is involved in a frontal collision, the shock is great enough to overcome the predetermine level of the front or center air bag sensor. When a safing sensor and a front air bag sensor and/or the center air bag sensor go on simultaneously, it causes the squib of the air bag to ignite and the air bag is deployed automatically. The inflated bag breaks open the steering wheel pad.
The connector of the air bag contains a short spring plate, which provides an activation prevention mechanism. When the connector is disconnected, the short spring plate automatically connects the power source and grounding terminals of the inflator module (squib) to prevent static electricity from deploying the air bag.
Front Air Bag Sensor
The front sensors, located inside each front fender, detect deceleration force above a predetermined limit. They must be securely fastened to their mounts at all times.
The center air bag sensor is mounted on the floor inside the rear of the center cluster. The center sensor determines whether or not the air bag should be deployed and is also used to diagnose system malfunctions.Spiral Cable
The spiral cable, part of the combination switch, ensures uninterrupted electrical contact to the air bag while allowing rotation of the steering wheel. The spiral cable is also referred to as a clock spring.Air Bag
The air bag, located in the steering wheel pad, deploys in the event of a frontal collision of sufficient force. Special precautions must be taken when performing service on a vehicle equipped with an air bag.Warning Lamp
The air bag warning lamp, located on the combination meter, is used to alert the driver of a malfunction within the air bag system.
DISARMING THE SYSTEM
- Turn the ignition switch to the Lock position.
- Disconnect the negative battery terminal and isolate it by wrapping it with electrical tape.
- Wait at least 90 seconds from the time that the ignition switch is turned to the lock position and the battery is disconnected before performing any further work.
ENABLING THE SYSTEM
- Reconnect the negative battery cable.
- Perform the air bag warning light check by turning the ignition key to the On or Acc positions, but do NOT start the engine. The air bag warning lamp will illuminate for approximately 6 seconds. If no malfunctions are detected in the system, the warning light will go off. If it stays on, bring the vehicle to a qualified technician, otherwise the air bag may not deploy in a collision, causing personal injury or death.