Supplemental Restraint System (diagnostics - Introduction) Lexus IS F I

PRECAUTION

HINT

1. In the airbag system, the center airbag sensor assembly, front airbag sensor LH and RH, side airbag sensor LH and RH, and rear airbag sensor LH and RH are collectively referred to as the airbag sensors. The steering pad, front passenger airbag assembly, front seat side airbag assembly, curtain shield airbag assembly, center airbag sensor assembly, front airbag sensor, side airbag sensor, rear airbag sensor, seat position airbag sensor, front seat inner belt assembly, or front seat outer belt assembly, rear seat outer belt assembly or occupant classification ECU are collectively referred to as the SRS parts.

Note. Malfunction symptoms of the SRS are difficult to confirm, so DTCs are the most important source of information when troubleshooting. When troubleshooting the SRS, always inspect DTCs before disconnecting the battery. Even in the case of a minor collision that does not cause the SRS to deploy, the SRS parts should be inspected. Before beginning repairs, remove the airbag sensors if any kind of shock is likely to occur to the airbag sensors during the operation. Never use SRS parts from another vehicle. When replacing parts, replace them with new ones. Never disassemble or repair any of the SRS parts in order to reuse them. If any of these parts have been dropped, or any defect is found (e.g. cracks, dents or any other defects) in any of the housings, brackets or connectors, replace the part with a new one. Use a volt/ohmmeter with high impedance (10 kohms/V minimum) for troubleshooting the electrical circuits. Information labels are attached near the SRS parts. Follow the instructions noted in the caution. After work on the SRS is completed, perform an SRS warning light check. Refer to DIAGNOSIS SYSTEM . When the cable is disconnected from the negative (-) battery terminal, the memory will be cleared. Because of this, be sure to make a record of the contents memorized in each system before starting work. When work is finished, adjust each system to its previous state. Never use a backup power supply for the purpose of retaining the memory of vehicle electronic systems. If the vehicle is equipped with a mobile communication system, refer to PRECAUTION "Mobile Communication System".

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1. HANDLING PRECAUTIONS FOR AIRBAG SENSORS Before starting the following operations, wait for at least 90 seconds after disconnecting the cable from the negative (-) battery terminal: Replacement of the airbag sensors. Adjustment of the front/rear doors of the vehicle equipped with front seat 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 airbag sensors which have been dropped. Do not disassemble the airbag sensors.
2. INSPECTION PROCEDURE FOR VEHICLE INVOLVED IN ACCIDENT If any of the airbags have not deployed, confirm the DTCs by checking the SRS warning light. If there is any malfunction in the SRS airbag system, perform troubleshooting. If any of the airbags have deployed, replace the airbag sensors and check the installation condition.
3. FUNCTION OF SRS CONNECTORS SRS connectors are located as shown in the following illustration. No. Connector Type Application (1) Terminal Twin-Lock Mechanism Connectors 2, 4, 6, 9, 10, 15, 16, 20, 22, 27, 28 (2) Activation Prevention Mechanism Connectors 2, 4, 5, 7, 9, 11, 13, 27, 29, 31, 33 (3) Half Connection Prevention Mechanism Connectors 6, 10, 15, 20, 22, 28 (4) Connector Position Assurance Mechanism Connector 18 (5) Connector Lock Mechanism (1) Connectors 8, 12, 14, 30, 32, 34 (6) Connector Lock Mechanism (2) Connectors 2, 4 (7) Improper Connection Prevention Lock Mechanism Connectors 1, 3 Connectors in the SRS 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 to ensure high reliability (see step 3 above). 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 force 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 the holder is connected, 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), CURTAIN SHIELD AIRBAG ASSEMBLY, DRIVER SIDE KNEE AIRBAG ASSEMBLY AND FRONT PASSENGER SIDE KNEE AIRBAG ASSEMBLY 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 ASSEMBLY (SQUIB SIDE), CURTAIN SHIELD AIRBAG ASSEMBLY, DRIVER SIDE KNEE AIRBAG ASSEMBLY AND FRONT PASSENGER SIDE KNEE AIRBAG ASSEMBLY Connect the connector. 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 ASSEMBLY (INSTRUMENT PANEL WIRE ASSEMBLY SIDE) 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 ASSEMBLY (INSTRUMENT PANEL WIRE ASSEMBLY 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 connected, 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 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 CONNECTORS FOR FRONT SEAT OUTER BELT ASSEMBLY AND REAR SEAT OUTER BELT ASSEMBLY HINT: Tape the screwdriver tip before use. Release the look button (black part) of the connector using a screwdriver. Insert the screwdriver tip between the connector and the base, and then raise the connector.
11. CONNECTION OF CONNECTORS FOR 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 locked, a click sound can be heard.)
12. 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 locked, a click sound can be heard.) HINT: The retainer is locked when the holder is connected.
13. 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 locked, 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.
14. DISCONNECTION OF CONNECTORS 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 part A 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.
15. 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 engaged, the housing lock (white part) will slide. Be sure not to hold the housing lock (white part) and part A, as it may result in an insecure fit.
16. 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 can be disconnected. HINT: Be sure to hold both outer flank sides. Holding the top and bottom will make disconnection difficult.
17. 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 connected, the outer will slide. Be sure not to hold the outer while connecting, as it may result in an insecure fit.

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1. GENERAL FRONTAL COLLISION The driver airbag, front passenger airbag, driver side knee airbag and front passenger side knee airbag are designed to supplement seat belts in the event of a front collision in order to help reduce shock to the head, chest and knee. Frontal collisions are detected by the center airbag sensor and two front airbag sensors. The driver airbag, front passenger airbag, driver side knee airbag, front passenger side knee airbag, front seat belt pretensioners and rear seat belt pretensioners then operate simultaneously. SIDE COLLISION The front seat side airbag and curtain shield airbag are designed in the event of a side collision in order to help reduce shock to the driver, front passenger and rear outer passengers. Side collisions are detected by the side airbag sensor installed in the bottom of the center pillar and the rear airbag sensor installed in the bottom of the rear pillar. Front side collisions are detected by the side airbag sensor, causing the front seat side airbag and curtain shield airbag to deploy simultaneously. Rear side collisions are detected by the rear airbag sensor to deploy only the curtain shield airbag.
2. CONSTRUCTION AND OPERATION FRONT AIRBAG SENSOR The front airbag sensors are installed on the right and left radiator supports respectively. The front airbag sensor uses an electrical type 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 respectively. The side airbag sensor uses an electrical type deceleration sensor. 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 respectively. The rear airbag sensor uses an electrical type deceleration sensor. 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 General The center airbag sensor is installed on the center floor under the console box. The center airbag sensor consists of a deceleration sensor, safing sensor, ignition control circuit, and diagnostic circuit, etc. The center airbag sensor receives signals from the deceleration sensor and safing sensor built into the center airbag sensor and front airbag sensor, and determines whether the driver airbag, front passenger airbag, driver side knee airbag, front passenger side knee airbag, front seat belt pretensioners and rear seat belt pretensioners should be activated. In addition, the center airbag sensor diagnoses system malfunctions. The center airbag sensor receives signals from the deceleration sensor and the safing sensor built into the center airbag sensor, the side airbag sensor and the rear airbag sensor, and determines whether the front seat side airbag and the curtain shield airbag should be activated. In addition, the center airbag sensor diagnoses system malfunctions. The center airbag sensor sends the airbag deployment signal to the ECM through CAN (Controller Area Network) to operate the fuel pump control. Deceleration sensor and ignition control circuit The deceleration sensor is built into the center airbag sensor, front airbag sensor, side airbag sensor and rear airbag sensor, and the distortion created based on the deceleration of the vehicle during a frontal, front side or rear side collision is converted into an electric signal. The ignition control circuit performs calculations based on the signal output from the deceleration sensors of the center airbag sensor, front airbag sensor, side airbag sensor and rear airbag sensor. If the calculated values are greater than the specified values, it activates an ignition operation. Safing sensor The safing sensor is built into the center airbag sensor. During a frontal, front side or rear side collision, the sensor turns on and outputs an ON signal to the center airbag sensor if a deceleration rate sent to the safing sensor is greater than the specified value. 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 turns on the SRS warning light on the combination meter 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 combination meter assembly. It comes on to inform the driver of system trouble when a malfunction is detected in self-diagnosis of the center airbag sensor. Under normal operating conditions, when the engine switch is turned on (IG), the warning light comes on for approximately 6 seconds and then goes off.
3. DEPLOYMENT CONDITION If 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 is designed to turn on at a lower deceleration rate than the deceleration sensor. The center airbag sensor assembly determines whether 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 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 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 side airbag assembly deploys, the curtain shield airbag assembly will also deploy, regardless of whether the signal is output from the rear airbag sensor.

HOW TO PROCEED WITH TROUBLESHOOTING

HINT

*: Use the Techstream.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. CUSTOMER PROBLEM ANALYSIS Confirm problem symptoms. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/lexus/is-f/i-2007-2014/remont/hoistjack/#introduction) . NEXT: Go to next step
3. CHECK MULTIPLEX COMMUNICATION SYSTEM* Check for DTC output. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/communication-devices/#multiplex-communication-diagnostics-introduction__dtc-check-clear) . Result Result Proceed to Multiplex communication DTC is not output. A Multiplex communication DTC is output. B B --> INSPECT MULTIPLEX COMMUNICATION SYSTEM. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/lexus/is-f/i-2007-2014/remont/communication-devices/#multiplex-communication-diagnostics-introduction__how-to-proceed-with-troubleshooting) A: Go to next step
4. CHECK CAN COMMUNICATION SYSTEM* Use the Techstream to check if the CAN communication system is functioning normally. HINT: Refer to Bus Check for the CAN communication system. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/communication-devices/#can-communication-system-diagnostics__diagnosis-system) . The center airbag sensor assembly is connected to the CAN communication system. Therefore, before starting troubleshooting, make sure to check that there is no trouble in the CAN communication system. Result Result Proceed to CAN communication DTC is not output. A CAN communication DTC is output. B B --> INSPECT CAN COMMUNICATION CIRCUIT. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/lexus/is-f/i-2007-2014/remont/communication-devices/#can-communication-system-diagnostics__how-to-proceed-with-troubleshooting) A: Go to next step
5. SRS WARNING LIGHT CHECK Proceed to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . NEXT: Go to next step
6. CHECK FOR DTC* Proceed to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Result Result Proceed to DTC is output. A DTC is not output. B B --> GO TO STEP 9 A: Go to next step
7. DIAGNOSTIC TROUBLE CODE CHART Proceed to «DIAGNOSTIC TROUBLE CODE CHART»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction__diagnostic-trouble-code-chart) . NEXT --> GO TO STEP 9
8. SYMPTOM SIMULATION Proceed to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . NEXT: Go to next step
9. PROBLEM SYMPTOMS TABLE Proceed to «PROBLEM SYMPTOMS TABLE»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction__problem-symptoms-table) . NEXT: Go to next step
10. CIRCUIT INSPECTION* NEXT: Go to next step
11. IDENTIFICATION OF PROBLEM NEXT: Go to next step
12. REPAIR OR REPLACEMENT NEXT: Go to next step
13. CONFIRMATION TEST NEXT --> END

PROBLEM SYMPTOMS TABLE

HINT

1. Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
2. Inspect the fuses and relays related to this system before inspecting the suspected areas below.

AIRBAG SYSTEM

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1. CENTER AIRBAG SENSOR ASSEMBLY Terminal No. Terminal Symbol Destination J47-1 P2+ Front passenger airbag assembly (Front passenger side squib 2nd step) J47-2 P2- Front passenger airbag assembly (Front passenger side squib 2nd step) J47-3 P- Front passenger airbag assembly (Front passenger side squib) J47-4 P+ Front passenger airbag assembly (Front passenger side squib) J47-5 D+ Steering pad (Driver side squib) J47-6 D- Steering pad (Driver side squib) J47-7 D2- Steering pad (Driver side squib 2nd step) J47-8 D2+ Steering pad (Driver side squib 2nd step) J47-9 DK+ Driver side knee airbag assembly (Driver side knee airbag squib) J47-10 DK- Driver side knee airbag assembly (Driver side knee airbag squib) J47-13 CANH CAN communication line J47-16 SIL DLC3 J47-17 P-AB Clock assembly (Passenger airbag ON/OFF indicator)*1 Integration control and panel assembly (Passenger airbag ON/OFF indicator)*2 J47-18 GSW Main body ECU J47-19 PK+ Front passenger side knee airbag assembly (Front passenger side knee airbag squib) J47-20 PK- Front passenger side knee airbag assembly (Front passenger side knee airbag squib) J47-21 IG2 IGN fuse J47-22 CANL CAN communication line J47-23 PAON Clock assembly (Passenger airbag ON/OFF indicator)*1 Integration control and panel assembly (Passenger airbag ON/OFF indicator)*2 J47-24 GSW3 DCM (Telematics transceiver) J47-25 E1 Ground J47-26 E2 Ground J47-27 -SR Front airbag sensor RH J47-28 -SL Front airbag sensor LH J47-29 +SR Front airbag sensor RH J47-30 +SL Front airbag sensor LH Q32-1 PD- Front seat outer belt assembly LH (Front driver side pretensioner squib) Q32-2 PD+ Front seat outer belt assembly LH (Front driver side pretensioner squib) Q32-3 ED Driver side shield ground Q32-4 PDR+ Rear seat outer belt assembly LH (Rear driver side pretensioner squib) Q32-5 PDR- Rear seat outer belt assembly LH (Rear driver side pretensioner squib) Q32-6 ICD- Curtain shield airbag assembly LH (Driver side curtain shield squib) Q32-7 ICD+ Curtain shield airbag assembly LH (Driver side curtain shield squib) Q32-8 BCD+ Rear airbag sensor LH Q32-9 SFD+ Front seat side airbag assembly LH (Front driver side - side squib) Q32-10 SFD- Front seat side airbag assembly LH (Front driver side - side squib) Q32-11 DBE+ Front seat inner belt assembly LH (Driver side seat belt buckle switch) Q32-12 DBE- Front seat inner belt assembly LH (Driver side seat belt buckle switch) Q32-13 DSP- Seat position airbag sensor Q32-14 DSP+ Seat position airbag sensor Q32-15 BCD- Rear airbag sensor LH P14-1 PPR- Rear seat outer belt assembly RH (Rear passenger side pretensioner squib) P14-2 PPR+ Rear seat outer belt assembly RH (Rear passenger side pretensioner squib) P14-3 EP Passenger side shield ground P14-4 PP+ Front seat outer belt assembly RH (Front passenger side pretensioner squib) P14-5 PP- Front seat outer belt assembly RH (Front passenger side pretensioner squib) P14-6 SFP- Front seat side airbag assembly RH (Front passenger side - side squib) P14-7 SFP+ Front seat side airbag assembly RH (Front passenger side - side squib) P14-8 BCP+ Rear airbag sensor RH P14-9 ICP+ Curtain shield airbag assembly RH (Front passenger side curtain shield squib) P14-10 ICP- Curtain shield airbag assembly RH (Front passenger side curtain shield squib) P14-11 BCP- Rear airbag sensor RH P14-12 FSR+ Occupant classification ECU P14-13 FSR- Occupant classification ECU HINT: *1: w/ Navigation system *2: w/o Navigation system

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1. CHECK DLC3 Check the DLC3. Refer to «GENERAL INFORMATION»(/lexus/is-f/i-2007-2014/remont/hoistjack/#introduction) .
2. SYMPTOM SIMULATION HINT: The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. Then the same or similar conditions and the environment in which the problem occurred in the customer's vehicle should be reproduced. No matter how experienced or skilled a technician may be, if he/she proceeds to troubleshooting without confirming the problem symptoms, he/she will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting. Vibration method: When vibration seems to be the major cause. HINT: Perform the simulation method only during the primary check period of approximately 6 seconds after the engine switch is turned on (IG). Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs. HINT: Shaking the relays too strongly may result in open relays. Slightly shake the connector vertically and horizontally. Slightly shake the wire harness vertically and horizontally. The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.
3. FUNCTION OF SRS WARNING LIGHT Primary check Turn the engine switch off. Wait for at least 2 seconds, then turn the engine switch on (IG). The SRS warning light comes on for approximately 6 seconds and the diagnosis of the airbag system (including the seat belt pretensioners) is performed. HINT: If trouble is detected during the primary check, the SRS warning light remains on even after the primary check period of approximately 6 seconds. Constant check After the primary check, the center airbag sensor assembly constantly monitors the airbag system for trouble. HINT: If trouble is detected during the constant check, the center airbag sensor assembly functions as follows: The SRS warning light comes on. The SRS warning light goes off, and then comes on. This blinking pattern indicates a source voltage drop. The SRS warning light goes off 10 seconds after the source voltage returns to normal. Review When the airbag system is normal: The SRS warning light comes on only during the primary check period of approximately 6 seconds after the engine switch is turned on (IG). When the airbag system has trouble: The SRS warning light remains on even after the primary check period. The SRS warning light goes off after the primary check, but comes on again during the constant check. The SRS warning light does not come on when turning the engine switch from off to on (IG). HINT: The center airbag sensor assembly functions to keep the SRS warning light on if the airbag has been deployed.
4. SRS WARNING LIGHT CHECK Turn the engine switch on (IG), and check that the SRS warning light comes on for approximately 6 seconds (primary check). Check that the SRS warning light goes off approximately 6 seconds after the engine switch is turned on (IG) (constant check). HINT: When any of the following symptoms occur, refer to Problem Symptoms Table. Refer to «PROBLEM SYMPTOMS TABLE»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction__problem-symptoms-table) . The SRS warning light comes on occasionally after the primary check period. The SRS warning light comes on, but a DTC is not output. The engine switch is turned from off to on (IG), but the SRS warning light does not come on.
5. FUNCTION OF PASSENGER AIRBAG ON/OFF INDICATOR Initial check Turn the engine switch on (IG). The passenger airbag ON/OFF indicator comes on for approximately 4 seconds, then goes off for approximately 2 seconds. Approximately 6 seconds after the engine switch is turned on (IG), the passenger airbag ON/OFF indicator will be ON/OFF depending on the conditions listed below. Front Passenger Seat Condition Passenger Airbag ON/OFF Indicator SRS Warning Light ON Indicator OFF Indicator Vacant OFF OFF OFF Adult is seated. ON OFF OFF Child is seated. OFF ON OFF Child restraint system is set. OFF ON OFF Front passenger occupant classification failure OFF ON ON HINT: The passenger airbag ON/OFF indicator is based on the timing chart below in order to check the indicator light circuit. When the occupant classification system has trouble, both the SRS warning light and the passenger airbag ON/OFF indicator ("OFF") come on. In this case, check the DTCs in the airbag system first. Then troubleshoot the occupant classification system if DTC B1650/32 is detected, and troubleshoot the passenger airbag ON/OFF indicator if DTC B1660/43 is detected.
6. PASSENGER AIRBAG ON/OFF INDICATOR CHECK Turn the engine switch on (IG). Check that the passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds. HINT: Refer to the table in step 5 regarding the passenger airbag ON/OFF indicator when the engine switch is turned on (IG) and approximately 6 seconds pass.
7. ACTIVATION PREVENTION MECHANISM FUNCTION OF ACTIVATION PREVENTION MECHANISM An activation prevention mechanism is built into the connector (on the center airbag sensor assembly side) of the airbag system squib circuit to prevent accidental airbag activation. This mechanism closes the circuit when the connector is disconnected by bringing the short spring into contact with the terminals and insulating the circuit from external power sources to prevent accidental airbag activation. RELEASING OF ACTIVATION PREVENTION MECHANISM To release the activation prevention mechanism, insert a piece of paper with the same thickness as the male terminal (approximately 0.5 mm (0.020 in.)) between the terminals and the short spring to break the connection. Refer to the following illustrations concerning connectors utilizing the activation prevention mechanism and its release method. WARNING: Never release the activation prevention mechanism on the squib connector even when inspecting with the squib disconnected. NOTE: Do not release the activation prevention mechanism unless specially directed by the troubleshooting procedure. To prevent the terminal and the short spring from being damaged, always use a piece of paper with the same thickness as the male terminal.

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Scheme 232

1. DTC CHECK (USING SST CHECK WIRE) Check the DTCs (Present trouble code). Turn the engine switch on (IG), and wait for approximately 60 seconds. Using SST, connect terminals TC and CG of the DLC3. SST: 09843-18040 NOTE: Connect the terminals to the correct positions to avoid a malfunction. Check the DTCs (Past trouble code). Using SST, connect terminals TC and CG of the DLC3. SST: 09843-18040 NOTE: Connect the terminals to the correct positions to avoid a malfunction. Turn the engine switch on (IG), and wait for approximately 60 seconds. Read the DTCs. Read the blinking patterns of the DTCs. As examples, the blinking patterns for the normal system code and trouble codes 11 and 31 are shown in the illustration. Normal system code indication (without past trouble code) The light blinks twice per second. Normal system code indication (with past trouble code) When a past trouble code is stored in the center airbag sensor assembly, the light blinks only once per second. Trouble code indication The first blinks indicate the first digit of the DTC. The second digit is indicated by blinks that occur after a 1.5-second pause. If there is more than 1 code, there will be a 2.5-second pause between each code. After all codes are shown, there will be a 4.0-second pause, and then all codes will be repeated. HINT: If 2 or more malfunctions are found, the indication begins with the smaller-numbered code. If DTCs are indicated without connecting the terminals, proceed to "TC and CG Terminal Circuit". Refer to «TC and CG Terminal Circuit»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostic-codes-symptom-tests) .
2. DTC CLEAR (USING SST CHECK WIRE) Clear the DTCs. When the engine switch is turned off, the DTCs are cleared. HINT: Depending on the DTC, the code may not be cleared by turning off the engine switch. In this case, proceed to the next procedure (see step 3 ). Using SST, connect terminals TC and CG of the DLC3, and then turn the engine switch on (IG). SST: 09843-18040 Disconnect terminal TC of the DLC3 within 3 to 10 seconds after the DTCs are output, and check if the SRS warning light comes on after 3 seconds. Within 2 to 4 seconds after the SRS warning light comes on, connect terminals TC and CG of the DLC3. The SRS warning light should go off within 2 to 4 seconds after connecting terminals TC and CG of the DLC3. Then, disconnect terminal TC within 2 to 4 seconds after the SRS warning light goes off. The SRS warning light comes on again within 2 to 4 seconds after disconnecting terminal TC. Then, reconnect terminals TC and CG within 2 to 4 seconds after the SRS warning light comes on. Check if the SRS warning light goes off within 2 to 4 seconds after connecting terminals TC and CG of the DLC3. Also check if the normal system code is output within 1 second after the SRS warning light goes off. If DTCs are not cleared, repeat this procedure until the codes are cleared.
3. DTC CHECK (USING TECHSTREAM) Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG) and turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Trouble Code. Check the DTCs by following the prompts on the Techstream screen. HINT: Refer to the Techstream operator's manual for further details.
4. DTC CLEAR (USING TECHSTREAM) Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG) and turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Trouble Code. Clear the DTCs by following the prompts on the Techstream screen. HINT: Refer to the Techstream operator's manual for further details.

CHECK MODE PROCEDURE

1. CHECK MODE (SIGNAL CHECK): DTC CHECK Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG) and turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Utility / Signal Check. Select Signal Check, and proceed with checking using the Techstream. NOTE: Select Signal Check screen displayed on the Techstream to clear the output DTCs (both present and past). HINT: DTCs can be detected more sensitively in check mode than in normal diagnosis mode. Perform check mode inspection when a malfunction in each squib circuit is suspected even after the normal system code is output through normal diagnosis mode inspection.

DATA LIST / ACTIVE TEST

HINT

Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

Note. In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

1. DATA LIST FOR CENTER AIRBAG SENSOR ASSEMBLY Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Data List. Check the values by referring to the table below. DATA LIST Tester Display Measurement Item/Range Normal Condition Diagnostic Note Driver Seat Position Driver seat position/ Forward: Seat position is forward Bkward: Seat position is backward Fail: Failure detected Forward/Bkward - Passenger Classification Passenger classification/ NG: Date is not determined OFF: Vacant CHILD: Child (less than 36 kg (79.37 lb)) is seated AF05: Adult (36 to 54 kg (79.37 to 119.05 lb)) is seated AM50: Adult (more than 54 kg (119.05 lb)) is seated FAIL: A failure is detected OFF/CHILD/AF05/AM50 - Driver Buckle SW Driver buckle switch/ Unset: The seat belt is not fastened Set: The seat belt is fastened NG: Data is not determined Unset/Set - Passenger Buckle SW Passenger buckle switch/ Unset: The seat belt is not fastened Set: The seat belt is fastened NG: Data is not determined Unset/Set - Display Type Information Display type information/ LR: The display is indicated by LH/RH DP: The display is indicated by Driver/Passenger DP - Number of Past DTC Number of past DTC/ Min.: 0, Max.: 255 0

DIAGNOSTIC TROUBLE CODE CHART

If a trouble code is displayed during the DTC check, check the circuit listed for the code in the table below (refer to the appropriate information).

HINT

1. When the SRS warning light remains on and the DTC output is the normal system code, a voltage source drop is likely to occur. This malfunction is not stored in the memory by the center airbag sensor assembly. If the power source voltage returns to normal, the SRS warning light will automatically go off.
2. When 2 or more codes are indicated, the code with the lower number appears first.
3. If a code is not listed on the display chart, the center airbag sensor assembly may have failed.
4. In the case of any malfunction concerning an open circuit, short to ground, or short to B+ due to a squib, other trouble codes may not be detected. In this case, repair the malfunction currently indicated and then perform malfunction diagnosis again.
5. Mark in the check mode column: *1: DTC does not correspond to check mode. *2: DTC corresponds to check mode.
6. The mark shown below is applied to DTC B1660/43. *3: w/ Navigation System *4: w/o Navigation System

AIRBAG SYSTEM

See also:
• PRECAUTION
• DTC CHECK / CLEAR
• HOW TO PROCEED WITH TROUBLESHOOTING
• DIAGNOSIS SYSTEM
• HOW TO PROCEED WITH TROUBLESHOOTING
• SRS Warning Light Remains ON
• DIAGNOSIS SYSTEM
• DIAGNOSTIC TROUBLE CODE CHART
• PROBLEM SYMPTOMS TABLE