Airbag System (Diagnostics - Introduction): Other Lexus GS III рестайлинг

PRECAUTION

Note. 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 as necessary 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 SRS parts is completed, perform the SRS warning light check. Refer to 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 in the INTRODUCTION service information. See PRECAUTION . When disconnecting the negative (-) battery cable, initialize the following systems after the cable is reconnected. System Name See procedure Intuitive Parking Assist System Refer to INITIALIZATION Theft Deterrent System Variable Gear Ratio Steering System

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.

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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 has 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, 7, 8, 9, 10, 19, 20, 31, 32, 33, 34 (2) Activation Prevention Mechanism Connectors 10, 12, 14, 20, 22, 26, 30, 32, 34 (3) Half Connection Prevention Mechanism Connectors 5, 7, 9, 20, 24, 28, 32, 33 (4) Connector Position Assurance Mechanism Connector 7 (5) Connector Lock Mechanism (1) Connectors 11, 13, 21, 25, 29 (6) Connector Lock Mechanism (2) Connector 2, 4 (7) Improper Connection Prevention Lock Mechanism Connector 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 below 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 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), DRIVER SIDE KNEE AIRBAG, FRONT PASSENGER SIDE KNEE AIRBAG, CURTAIN SHIELD AIRBAG, FRONT SEAT OUTER BELT AND REAR SEAT OUTER BELT HINT: Tape 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 (SQUIB SIDE), DRIVER SIDE KNEE AIRBAG, FRONT PASSENGER SIDE KNEE AIRBAG, CURTAIN SHIELD AIRBAG, FRONT SEAT OUTER BELT AND REAR SEAT OUTER BELT 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 (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 (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 AIRBAG AND REAR SEAT AIRBAG 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 AIRBAG AND REAR SEAT AIRBAG 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 HINT: Perform the following procedures when replacing the holder. Pull the lever by pushing part A as shown in the illustration and disconnect the holder (with connectors). 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 Firmly insert the holder (with connectors) into the center airbag sensor 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 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 the part labeled A, as it may result in an insecure fit.
14. DISCONNECTION OF CONNECTORS FOR SIDE AIRBAG SENSOR AND REAR AIRBAG SENSOR While holding both the sides of the outer connector locking sleeve, slide the sleeve in the direction shown by the arrow. 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 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.

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1. GENERAL In conjunction with impact absorbing structure for a frontal collision, the SRS (Supplemental Restraint System) driver airbag, front passenger airbag, driver side knee airbag and front passenger side knee airbag were designed to supplement seat belts in the event of a frontal collision in order to help reduce shock to the head, chest and knee of the driver and front passenger. This system is a 3-sensor type airbag system to detect the impact during a frontal collision using the center airbag sensor assembly and front airbag sensors. It also operates the airbag system and seat belt pretensioner. In order to detect the extent of the collision during the initial stages of the collision in further detail, the front airbag sensors have been changed from mechanical type to electrical type deceleration sensors. Accordingly, the deployment of the driver airbag and front passenger airbag is controlled in two stages according to the severity of the impact. In conjunction with impact absorbing structure for a side collision, the front seat, rear seat and curtain shield airbag were designed to help reduce shock to the driver, front passenger, and rear outer passengers in the event of a side collision. The curtain shield airbag that helps reduce shock to the front and rear seat occupants with a single curtain shield airbag has been adopted. In conjunction with this system, the side airbag sensors have been installed at the bottom of the center pillars and the rear airbag sensors has been installed at the bottom of the rear pillars respectively. In this system, a front side collision is detected by the side airbag sensor in order to simultaneously deploy the front and rear side airbags. A rear side collision is detected by the rear airbag sensor and the center airbag sensor assembly in order to deploy the side airbag, rear side airbag and curtain shield airbag. The center airbag sensor assembly sends the airbag deployment signal to the hybrid ECU through BEAN (Body Electronics Area Network) and CAN (Controller Area Network) to cut the hybrid system's high voltage. For Lexus Link operation, the center airbag sensor sends the airbag deployment signal directly to the mayday ECU. The center airbag sensor assembly sends the airbag deployment signal to the body ECU via discrete line to operate collision door lock release control.
2. CONSTRUCTION AND OPERATION FRONT AIRBAG SENSOR The front airbag sensors are installed on the right and left radiator supports. The front airbag sensor ha a built-in deceleration sensor. The deceleration sensor is built into the front airbag sensor, and the distortion that is created in the sensor is converted into an electric signal based on the vehicle deceleration rate during a frontal collision. Accordingly, the extent of the initial collision can be detected in detail. SIDE AIRBAG SENSOR The side airbag sensors are installed on the bottom of the right and left center pillars. The side airbag sensor consists of the deceleration sensor and ignition control circuit. The deceleration sensor is built into the side airbag sensor, and the distortion that is created in the sensor is converted into an electric signal based on the vehicle deceleration rate during a front side collision. Accordingly, the extent of the initial collision can be detected in detail. REAR AIRBAG SENSOR The rear airbag sensors are installed on the right and left rear pillars. The rear airbag sensor consists of the deceleration sensor and ignition control circuit. The deceleration sensor is built into the rear airbag sensor, and the distortion that is created in the sensor is converted into an electric signal based on the vehicle deceleration rate during a rear side collision. Accordingly, the extent of the initial collision can be detected in detail. CENTER AIRBAG SENSOR ASSEMBLY General The center airbag sensor assembly is installed on the center floor under the console box. The center airbag sensor assembly consists of the deceleration sensor, safing sensor, electronic safing sensor, ignition control circuit and diagnostic circuit. The center airbag sensor assembly receives signals from the deceleration sensor and safing sensor built into the center airbag sensor assembly and front airbag sensor. Then the center airbag sensor assembly determines whether or not the driver airbag, front passenger airbag, driver side knee airbag, front passenger side knee airbag and front seat belt pretensioners, rear seat belt pretensioners should be activated, and diagnoses system malfunctions. The center airbag sensor assembly causes the front and rear seat airbag and the curtain shield airbag assembly to deploy when receiving signals from the side airbag sensor. The center airbag sensor assembly receives signals from the deceleration sensor and the electronic safing sensor built into the center airbag sensor assembly and the rear airbag sensor, and determines whether or not the side airbag, rear side airbag and curtain shield airbag assembly should be activated, and diagnoses system malfunctions. During a collision, the center airbag sensor sends a collision detection signal to the hybrid ECU via the BEAN bus line, and the center airbag sensor's GSW2 terminal sends a signal directly to the hybrid ECU. When either signal is input into the hybrid ECU, the hybrid system's high voltage is cut. The center airbag sensor assembly sends the airbag deployment signal to the main body ECU through discrete line to operate collision door lock release control. For Lexus Link operation, the center airbag sensor sends the airbag deployment signal directly to the mayday ECU. Deceleration sensor and ignition control circuit The deceleration sensor is built into the center airbag sensor assembly. The ignition control circuit performs calculations based on the signal output from the deceleration sensors of the center airbag sensor assembly and front airbag sensor. If the calculated values are greater than the specified values, it activates ignition operation. Safing sensor The safing sensor is built into the center airbag sensor assembly. During a frontal collision, the sensor turns on and outputs an ON signal to the center airbag sensor assembly if a deceleration rate greater than the specified value is applied to the safing sensor. Electronic safing sensor The electronic safing sensor is built into the center airbag sensor assembly. During a side collision, the sensor turns on and outputs an ON signal to the center airbag sensor assembly if a deceleration rate greater than the specified value is applied to the electronic safing sensor. Backup power source The backup power source consists of a power supply capacitor and a DC-DC converter. When the power system does not function during a collision, the power supply capacitor discharges and supplies electric power to the system. The DC-DC converter operates as a boosting transformer when the battery voltage falls below a predetermined level. Diagnostic circuit This circuit constantly diagnoses system malfunctions. When a malfunction is detected, it lights up the SRS warning light on the telltale light assembly to inform the driver. Memory circuit When a malfunction is detected in the diagnostic circuit, it is coded and stored in the memory circuit. SRS WARNING LIGHT The SRS warning light is located on the telltale light assembly. It comes on to inform the driver of system trouble when a malfunction is detected in self-diagnosis of the center airbag sensor assembly. Under normal operating conditions when the power switch is turned on (IG), it comes on for approximately 6 seconds and then goes off.
3. DEPLOYMENT CONDITION When the vehicle collides and the shock is greater than the specified value, the SRS is activated automatically. The center airbag sensor assembly includes the safing sensor and deceleration sensor. The safing sensor was designed to turn on at a smaller deceleration rate than the deceleration sensor. The center airbag sensor assembly determines whether or not ignition is necessary based on signals from the deceleration sensor and the front airbag sensor (*1). If the safing sensor turns on simultaneously, current flows to the squibs to deploy the SRS as shown in the illustration below. HINT: *1: In case of front collision, the ignition signal could be output with the deceleration sensor ON signal even without a signal from the front airbag sensor. The center airbag sensor assembly determines whether or not ignition is necessary based on signals from the side airbag sensor. If the safing sensor turns on simultaneously, current flows to the squib to deploy the SRS as shown in the illustration below. The center airbag sensor assembly determines whether or not ignition is necessary based on signals from the rear airbag sensor. If the safing sensor turns on simultaneously, current flows to the squib to deploy the SRS as shown in the illustration below (*1). HINT: *1: If the front seat airbag assembly deploys, the curtain shield airbag assembly will also deploy, regardless of whether the signal is output from the rear airbag sensor.

CHECK MODE PROCEDURE

1. CHECK MODE (SIGNAL CHECK) Connect the Techstream to the DLC3. Turn the power switch ON (IG). Select the "SIGNAL CHECK", and proceed checking with the Techstream. NOTE: Select the "SIGNAL CHECK" from the "DTC CHECK" screen displayed on the Techstream to clear the output DTCs (both present and past). HINT: Check mode is more sensitive to malfunctions than normal mode. If the normal system code is output in normal mode even when a sensor signal malfunctions suspected, perform the inspection in check mode.