Lexus IS250 IS220d GSE20 ALE20 - SUPPLEMENTAL RESTRAINT SYSTEM
AIRBAG SYSTEM - PRECAUTION
- CAUTION:
(The SRS is equipped with a backup power source, so that if work is started within 90 seconds after disconnecting the negative (-) terminal cable of the battery, the SRS may be deployed.)
- NOTICE:
System Name | See procedure |
Parking Assist Monitor System | |
Power Window Control System |
- HINT:
- In the airbag system, the center airbag sensor assembly, front airbag sensor LH and RH, driver side and front passenger side - side airbag sensor, driver side and front passenger side rear airbag sensor are collectively referred to as the airbag sensors.
1.HANDLING PRECAUTIONS FOR AIRBAG SENSORS |
Before starting the following operations, wait for at least 90 seconds after disconnecting the negative (-) terminal cable from the battery:
Replacement of the airbag sensors.
Adjustment of the front/rear doors of the vehicle equipped with the side airbag and curtain shield airbag (fitting adjustment).
When connecting or disconnecting the airbag sensor connectors, ensure that each sensor is installed in the vehicle.
Do not use the airbag sensors which have been dropped during the operation or transportation.
Do not disassemble the airbag sensors.
2.INSPECTION PROCEDURE FOR VEHICLE INVOLVED IN ACCIDENT |
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.
When any of the airbags have deployed, replace the airbag sensors and check the installation condition.
3.SRS CONNECTORS |
SRS connectors are located as shown in the following illustration.
No. | Item | Application |
(1) | Terminal Twin-Lock Mechanism | Connectors 5, 6, 11, 12, 16, 18, 29, 30 |
(2) | Activation Prevention Mechanism | Connectors 2, 4, 5, 7 ,9 ,19, 23, 25, 27, 30, 31 |
(3) | Half Connection Prevention Mechanism | Connectors 6, 11, 16, 18, 29 |
(4) | Connector Position Assurance Mechanism | Connector 14 |
(5) | Connector Lock Mechanism (1) | Connectors 8, 10, 20, 24, 26, 28, 32 |
(6) | Connector Lock Mechanism (2) | Connectors 2, 4 |
(7) | Improper Connection Prevention Lock Mechanism | Connectors 1, 3 |
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 on the previous page to ensure high reliability.

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.
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.
Half connection prevention mechanism:
If the connector is not completely connected, the connector is disconnected due to the spring operation so that no continuity exists.
Connector position assurance mechanism:
Only when the housing lock (white part) is completely engaged, the CPA (yellow part) slides, which completes the connector engagement.
Connector lock mechanism (1):
Locking the connector lock button connects the connector securely.
Connector lock mechanism (2):
Both the primary lock with holder lances and the secondary lock with retainer prevent the connectors from becoming disconnected.
Improper connection prevention lock mechanism:
When connecting the holder, the lever is pushed into the end by rotating around the A axis to lock the holder securely.
4.DISCONNECTION OF CONNECTORS FOR STEERING PAD, FRONT PASSENGER AIRBAG ASSEMBLY (SQUIB SIDE), DRIVER SIDE KNEE AIRBAG ASSEMBLY, FRONT PASSENGER SIDE KNEE AIRBAG ASSEMBLY, CURTAIN SHIELD AIRBAG ASSEMBLY, FRONT SEAT OUTER BELT ASSEMBLY AND REAR SEAT OUTER BELT ASSEMBLY |
- HINT:
- Tape up the screwdriver tip before use.
Release the lock button (yellow part) of the connector using a screwdriver.
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 ASSEMBLY (SQUIB SIDE), DRIVER SIDE KNEE AIRBAG ASSEMBLY, FRONT PASSENGER SIDE KNEE AIRBAG ASSEMBLY, CURTAIN SHIELD AIRBAG ASSEMBLY, FRONT SEAT OUTER BELT ASSEMBLY AND REAR SEAT OUTER BELT ASSEMBLY |
Connect the connector.
Push down securely on the lock button (yellow part) of the connector (When locking, a click sound can be heard.)
6.DISCONNECTION OF CONNECTOR FOR FRONT PASSENGER AIRBAG ASSEMBLY (INSTRUMENT PANEL WIRE SIDE) |
Place a finger on the slider, slide the slider to release the lock, and then disconnect the connector.
7.CONNECTION OF CONNECTOR FOR FRONT PASSENGER AIRBAG ASSEMBLY (INSTRUMENT PANEL WIRE SIDE) |
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 ASSEMBLY |
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 ASSEMBLY |
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 ASSEMBLY |
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.
Remove the holder.
Using a screwdriver, unlock the retainer.
Release the fitting lance and remove the holder.

Install the holder.
Install the connectors to the holder. (When locking, a click sound can be heard.)
- HINT:
- The retainer is locked when the holder is connected.
11.CONNECTION OF CONNECTOR FOR CENTER AIRBAG SENSOR ASSEMBLY |
Firmly insert the holder (with connectors) into the center airbag sensor assembly until it cannot be pushed any further.
Push the lever to connect the holder (with connectors). (When locking, a click sound can be heard.)
- HINT:
- The holder slides into the center airbag sensor assembly 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 |
Push down the housing lock (white part) and slide the CPA (yellow part). (At this time, the connector cannot be disconnected yet.)
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.
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 |
Before connecting the connectors, check that the position of the housing lock (white part) is as shown in the illustration.
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) and A part, as it may result in an insecure fit.
14.DISCONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR |

While holding the sides of the outer connector locking sleeve, slide the outer in the direction shown by the arrow.
When the connector lock is released, the connectors are disconnected.
- HINT:
- Be sure to hold both outer flank sides. Holding the top and bottom will make disconnection difficult.
15.CONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR |
Connect the connector as shown in the illustration (When locking, make sure that the outer returns to its original position and a click sound can be heard).
- HINT:
- When connecting, the outer will slide. Be sure not to hold the outer while connecting, as it may result in an insecure fit.