Section 832 (Introduction): Precaution

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

Further, if a mistake is made in servicing the supplemental restraint system, it is possible the SRS may fail to operate when required. Before 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 service information.

1. Malfunction symptoms of the supplemental restraint system are difficult to confirm, so the diagnostic trouble codes become the most important source of information when troubleshooting.

   When troubleshooting the supplemental restraint system, always inspect the diagnostic trouble codes before disconnecting the battery (See DIAGNOSTIC TESTS ).

   Fig 1: Identifying Negative Cable

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Work must be started after 90 seconds from the time the ignition switch is turned to the "LOCK" position and the negative (-) terminal cable is disconnected from the battery (The supplemental restraint system is equipped with a back-up power source so that if work is started within 90 seconds of disconnecting the negative (-) terminal cable from the battery, the SRS may deploy.).

   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 each memory system.

   Then when work is finished, reset the clock and audio systems as before.

   This vehicle has a power tilt and power telescopic steering column, front and rear power seats, power outside rear view mirror and power shoulder belt anchorage, which are all equipped with memory function and they can make a record of the memory contents except for rear power seat.

   Therefore, when the operation is finished, it is necessary to explain this to a customer and ask the customer to adjust the features and reset the memory. To avoid erasing the memory of each memory system, never use a back-up power supply from another battery.

3. Even in cases of a minor collision where the SRS does hot deploy, the steering wheel pad, front passenger airbag assembly, side airbag assembly and seat belt pretensioner should be inspected (See SYSTEM OPERATION CHECK , INSPECTION , and INSPECTION .
4. Never use SRS parts from another Vehicle. When replacing parts, replace them with new parts.
5. Before repairs, remove the airbag sensor if shocks are likely to be applied to the sensor during repairs.
6. Never disassemble and repair the airbag sensor assembly, steering wheel pad, front passenger airbag assembly, side airbag assembly or seat belt pretensioner.
7. If the airbag sensor assembly, steering wheel pad, front passenger airbag assembly, side airbag assembly or seat belt pretensioner has been dropped, or if there are cracks, dents or other defects in the case, bracket or connector, replace them with new ones.
8. Do not directly expose the airbag sensor assembly, steering wheel pad, front passenger air bag assembly, side airbag assembly or seat belt pretensioner to hot air or flames.
9. Use a volt/ohmmeter with high impedance (10 kΩ/V minimum) for troubleshooting of the electrical circuit.
10. Information labels are attached to the periphery of the SRS components. Follow the instructions oh the notices.
11. After work on the supplemental restraint system is completed, check the SRS warning light (See DIAGNOSTICS ).

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 POWER TILT AND POWER TELESCOPIC STEERING COLUMN concerning correct steering wheel installation.

Fig 2: Identifying Steering Ring Marks

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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.

   Storing the pad with its metallic surface facing upward may lead to a serious accident if the airbag deploys for some reason. In addition do not store a steering wheel pad on top of another one.

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 93°C (200°F), without high humidity and away from electrical noise.
5. When using electric welding, first disconnect the air-bag 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 DISPOSAL PROCEDURES ).

   Carry out the operation in a safe place away from electrical noise.

   Fig 3: Identifying Correct Placing

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002