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Precautions for vehicles equipped with srs airbag

The 1991 MR2 for USA specifications is equipped with an SRS (Supplemental Restraint System) airbag.

Failure to carry out service operations in the correct sequence could cause the airbag system to unexpectedly deploy during servicing, possibly leading to a serious accident.

Further, if a mistake is made in servicing the airbag system, it is possible the airbag may fail to operate when required. Before performing servicing (including removal or installation of parts, inspection or replacement), be sure to read the following items carefully, then follow the correct procedure described in this manual.


Locations of Airbag Components

  1. Malfunction symptoms of the airbag system are difficult to confirm, so the diagnostic codes become the most important source of information when troubleshooting. When troubleshooting the airbag system, always inspect the diagnostic codes before disconnecting the battery (See page AB-24).

  2. Work must be started after approx. 20 seconds or loner from the time the ignition switch is turned to the LOCK position and the negative (-) terminal cable is disconnected from the battery. (The airbag system is equipped with a back-up power source so that if work is started within 20 seconds of disconnecting the negative (-) terminal cable of the battery, the airbag may be deployed.) When the negative (-) terminal cable is disconnected from the battery, memory of the clock and audio systems will be cancelled. So before starting work, make a record of the contents memorized by the audio memory system. Then when work is finished, reset the audio system as before and adjust the clock. To avoid erasing the memory of each memory system, never use a back-up power supply from outside the vehicle.

  3. Even in cases of a minor collision where the airbag does not deploy, the front airbag sensors and the steering wheel pad should be inspected (See page AB-11).

  4. Never use airbag parts from another vehicle. When replacing parts, replace them with new parts.
  5. Before repairs, remove the airbag sensors if shocks are likely to be applied to the sensors during repairs.
  6. The center airbag sensor assembly contains mercury. After performing replacement, do not destroy the oil part. When scrapping the vehicle or replacing the center airbag sensor assembly itself, remove the center airbag sensor assembly and dispose of it as toxic waste.
  7. Never disassemble and repair the front airbag sensors, center airbag sensor assembly or steering wheel pad in order to reuse it.
  8. If the front airbag sensors, center airbag sensor assembly or steering wheel pad have been dropped, or if there are cracks, dents or other defects in the case, bracket or connector, replace them with new ones.
  9. Do not expose the front airbag sensors, center airbag sensor assembly or steering wheel pad directly to hot air or flames.
  10. Use a volt/ohmmeter with high impedance (10 kQ/V minimum) for troubleshooting of the electrical circuit.
  11. Information labels are attached to the periphery of the airbag components. Follow the instructions on the notices.
  12. After work on the airbag system is completed, perform the airbag warning light check (See page AB-29).

Front airbag sensor

  1. Never reuse the front airbag sensors involved in a collision when the airbag has deployed. (Replace both the left and right airbag sensors.)
  2. Install the front airbag sensor with the arrow on the sensor facing toward the front of the vehicle.
  3. The front airbag sensor set bolts and nuts have been anti-rust treated.
  4. When the sensor is removed, always replace the set bolts and nuts with new ones.
  5. The front airbag sensor is equipped with an electrical connection check mechanism. Be sure to lock this mechanism securely when connecting the connector. If the connector is not securely locked, a malfunction code will be detected by the diagnosis system (See page AB-9).

Spiral cable (in combination switch)

The steering wheel must be fitted correctly to the steering column with the spiral cable at the neutral position; otherwise cable disconnection and other troubles may result. Refer to page AB-16 of this manual concerning correct steering wheel installation.

Steering wheel pad (with airbag)

  1. When removing the steering wheel pad or handling a new steering wheel pad, it should be placed with the pad top surface facing up. In this case, the twin-lock type connector lock lever should be in the locked state and care should be taken to place it so the connector will not be damaged. And do not store a steering wheel pad on top of another one. (Storing the pad with its metallic surface up may lead to a serious accident if the airbag inflates for some reason.)

  2. Never measure the resistance of the airbag squib. (This may cause the airbag to deploy, which is very dangerous.)

  3. Grease should not be applied to the steering wheel pad and the pad should not be cleaned with detergents of any kind.

  4. Store the steering wheel pad where the ambient temperature remains below 90°C (200°F), without high humidity and away from electrical noise.
  5. When using electric welding, first disconnect the airbag connector (yellow color and 2 pins) under the steering column near the combination switch connector before starting work.
  6. When disposing of a vehicle or the steering wheel pad alone, the airbag should be deployed using an SST before disposal (See page AB-82). Perform the operation in a place away from electrical noise.

Center airbag sensor assembly

The connectors to the center airbag sensor assembly should be connected or disconnected with the sensor mounted on the floor. If the connectors are connected or disconnected while the center airbag sensor assembly is not mounted to the floor, it could cause undesired ignition of the airbag system.

Wire harness and connector

The airbag system's wire harness is integrated with the cowl wire harness assembly. The wires for the airbag wire harness are encased in a yellow corrugated tube. All the connectors for the system are also a standard yellow color. If the airbag system wire harness becomes disconnected or the connector becomes broken due to an accident, etc., repair or replace it as shown on page AB-21.