Air Bag Systems: Service Precautions

SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM: PRECAUTION

CAUTION:
* The vehicle is equipped with a Supplemental Restraint System (SRS), which consists of a steering pad, front passenger airbag, knee airbag, curtain shield airbag, front seat side airbag, seat belt pretensioner, center airbag sensor, front airbag sensor, side airbag sensor, rear airbag sensor, occupant classification ECU and seat position airbag sensor. Failure to carry out service procedures in the correct sequence could cause SRS parts to unexpectedly deploy and possibly lead to serious injuries. Furthermore, if a mistake is made when servicing SRS parts, they may fail to operate when required. Before performing servicing (including installation/removal, inspection and replacement of parts), be sure to read the following precautions.
* Before starting work, wait at least 90 seconds after the ignition switch has been turned off and after the cable of the negative (-) battery terminal has been disconnected. SRS parts are equipped with a backup power source. If work is started within 90 seconds of turning the ignition switch off and disconnecting the cable from the negative (-) battery terminal, SRS parts may deploy.
* Do not expose SRS parts directly to hot air or flames.
* Be sure to perform the initialization of the occupant classification ECU if any of the following conditions occur. If the initialization is not performed, the SRS may not operate properly.
* The occupant classification ECU is replaced.
* Accessories (seatback tray, seat cover, etc.) are installed onto the vehicle.
* The passenger seat is removed from the vehicle, and then reinstalled or replaced.
* The passenger airbag ON/OFF indicator light (OFF) comes on when the passenger seat is not occupied.
* The vehicle is brought to the workshop for repair due to an accident or collision.
NOTICE:
* Malfunction symptoms of SRS parts are difficult to confirm. DTCs are the most important source of information when troubleshooting. During troubleshooting, always confirm DTCs before disconnecting the cable from the negative (-) battery terminal.
* For minor collisions where SRS parts do not deploy, always inspect the SRS parts.
* Before performing repairs, remove airbag sensors if any kind of impact is likely to occur to an airbag sensor during repairs.
* Never use SRS parts from another vehicle. When replacing SRS parts, replace them with new ones.
* Never disassemble or attempt to repair SRS parts.
* If an SRS part has been dropped, or if there are any cracks, dents or other defects in the case, bracket or connector, replace the SRS part with a new one.
* Use an ohmmeter/voltmeter with high impedance (10 kOhms/V minimum) for troubleshooting the electrical circuits.
* Information labels are attached to the periphery of SRS parts. Follow the cautions and instructions on the labels.
* After work on the SRS is completed, perform the SRS warning light check Diagnosis System.
* When the cable is disconnected from the negative (-) battery terminal, the memory settings of each system will be cleared. Because of this, be sure to write down the settings of each system before starting work. When work is finished, reset the settings of each system as before. Never use a backup power supply from outside the vehicle, to avoid erasing the memory in a system.
* If the vehicle is equipped with a mobile communication system, refer to the precaution.
HINT
In the airbag system, the center airbag sensor, front airbag sensor LH and RH, side airbag sensor LH and RH, rear airbag sensor LH and RH are collectively referred to as the airbag sensors.

1. HANDLING PRECAUTIONS FOR AIRBAG SENSORS

(a) Before starting the following operations, wait for at least 90 seconds after disconnecting the cable from the negative (-) battery terminal:

(1) Replacement of the airbag sensors.

(2) Adjustment of the front/rear doors of a vehicle equipped with side airbags and curtain shield airbags (fitting adjustment).

(b) When connecting or disconnecting the airbag sensor connectors, ensure that each sensor is installed in the vehicle.

(c) Do not use airbag sensors which have been dropped during operation or transportation.

(d) Do not disassemble the airbag sensors.

2. INSPECTION PROCEDURE FOR VEHICLE INVOLVED IN ACCIDENT

(a) When the airbag has not deployed, confirm the DTCs by checking the SRS warning light. If there is any malfunction in the SRS airbag system, perform troubleshooting.

(b) When any of the airbags have deployed, replace the airbag sensors and check the installation condition.

3. SRS CONNECTORS

(a) SRS connectors are located as shown in the following illustration.

(b) All connectors in the SRS, except the seat position airbag sensor connector, are colored yellow to distinguish them from other connectors. These connectors have special functions, and are specially designed for the SRS. All SRS connectors use durable gold-plated terminals, and are placed in the locations shown below to ensure high reliability.

(1) Terminal twin-lock mechanism:

All connectors with a terminal twin-lock mechanism have a two-piece component consisting of a housing and a spacer. This design enables the terminal to be locked securely by two locking devices (the retainer and the lance) to prevent terminals from coming out.

(2) Activation prevention mechanism:

All connectors with an activation prevention mechanism contain a short spring plate. When these connectors are disconnected, the short spring plate creates a short circuit by automatically connecting the positive (+) and negative (-) terminals of the squib.

(3) Half connection prevention mechanism:

If the connector is not completely connected, the connector is disconnected by the spring force so that no continuity exists.

(4) Connector position assurance mechanism:

Only when the housing lock (white part) is completely engaged, the CPA (yellow part) slides, which completes the connector engagement.

(5) Connector lock mechanism (1):

Locking the connector lock button connects the connector securely.

(6) Connector lock mechanism (2):

Both the primary lock with holder lances and the secondary lock with retainer prevent the connectors from becoming disconnected.

(7) Improper connection prevention lock mechanism:

When connecting the holder, the lever is pushed into the lock position by rotating around the A axis to lock the holder securely.

4. DISCONNECTION OF CONNECTORS FOR STEERING PAD, FRONT PASSENGER AIRBAG (SQUIB SIDE), KNEE AIRBAG, CURTAIN SHIELD AIRBAG AND FRONT SEAT OUTER BELT

HINT
Tape the screwdriver tip before use.

(a) Release the lock button (yellow part) of the connector using a screwdriver.

(b) Insert the screwdriver tip between the connector and the base, and then raise the connector.

5. CONNECTION OF CONNECTORS FOR STEERING PAD, FRONT PASSENGER AIRBAG (SQUIB SIDE), KNEE AIRBAG, CURTAIN SHIELD AIRBAG AND FRONT SEAT OUTER BELT

(a) Connect the connector.

(b) Push down securely on the lock button (yellow part) of the connector. When locked, a click sound can be heard.

6. DISCONNECTION OF CONNECTOR FOR SPIRAL CABLE (INSTRUMENT PANEL WIRE SIDE) AND FRONT PASSENGER AIRBAG (INSTRUMENT PANEL WIRE SIDE)

(a) Place a finger on the slider, slide the slider to release the lock, and then disconnect the connector.

7. CONNECTION OF CONNECTOR FOR SPIRAL CABLE (INSTRUMENT PANEL WIRE SIDE) AND FRONT PASSENGER AIRBAG (INSTRUMENT PANEL WIRE SIDE)

(a) Connect the connector as shown in the illustration. When locking, make sure that the slider returns to its original position and a click sound can be heard.

HINT
When connecting, the slider will slide. Be sure not to touch the slider while connecting, as it may result in an insecure fit.

8. DISCONNECTION OF CONNECTORS FOR FRONT SEAT SIDE AIRBAG

(a) Place a finger on the slider, slide the slider to release the lock, and then disconnect the connector.

9. CONNECTION OF CONNECTORS FOR FRONT SEAT SIDE AIRBAG

(a) Connect the connector as shown in the illustration. When locking, make sure that the slider returns to its original position and a click sound can be heard.

HINT
When connecting, the slider will slide. Be sure not to touch the slider while connecting, as it may result in an insecure fit.

10. DISCONNECTION OF CONNECTOR FOR CENTER AIRBAG SENSOR

(a) Pull the lever by pushing part A as shown in the illustration and disconnect the holder (with connectors).

HINT
Perform the following procedures when replacing the holder.

(b) Remove the holder.

(1) Using a screwdriver, unlock the retainer.

(2) Release the fitting lance and remove the holder.

(1) Install the connectors to the holder. When locked, a click sound can be heard.

HINT
The retainer is locked when the holder is connected.

11. CONNECTION OF CONNECTOR FOR CENTER AIRBAG SENSOR

(a) Firmly insert the holder (with connectors) into the center airbag sensor until it cannot be pushed any further.

(b) Push the lever to connect the holder (with connectors). When locked, a click sound can be heard.

HINT
The holder slides into the center airbag sensor when it is being connected. Be sure not to hold the holder while connecting, as it may result in an insecure fit.

12. DISCONNECTION OF CONNECTOR FOR FRONT AIRBAG SENSOR

(a) Push down the housing lock (white part) and slide the CPA (yellow part). At this time, the connector cannot be disconnected yet.

(b) Push down the housing lock (white part) again and disconnect the connector.

HINT
Do not push down the A part shown in the illustration when disconnecting.

(c) After disconnecting the connector, check that the position of the housing lock (white part) is as shown in the illustration.

13. CONNECTION OF CONNECTOR FOR FRONT AIRBAG SENSOR

(a) Before connecting the connectors, check that the position of the housing lock (white part) is as shown in the illustration.

(b) Be sure to engage the connectors until they are locked. When locking, make sure that a click sound can be heard.

HINT
When connecting them, the housing lock (white part) slides. Be sure not to hold the housing lock (white part) or A part, as it may result in an insecure fit.

14. DISCONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR

(a) While holding the sides of the outer connector locking sleeve, slide the sleeve in the direction shown by the arrow.

(b) When the connector lock is released, the connectors are disconnected.

HINT
Be sure to hold both sides of the sleeve. Holding the top and bottom will make disconnection difficult.

15. CONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR

(a) Connect the connector as shown in the illustration (When locking, make sure that the outer connector locking sleeve returns to its original position and a click sound can be heard).

HINT
When connecting, the sleeve will slide. Be sure not to hold the sleeve while connecting, as it may result in an insecure fit.