Supplemental Restraint System (Diagnostics - Introduction): Diagnosis Lexus IS III

PROBLEM SYMPTOMS TABLE [04/2013 - ]

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. AIRBAG SENSOR ASSEMBLY Terminal No. Terminal Symbol Destination P31-1 SFR+ Side squib RH (Front seat airbag assembly RH) P31-2 SFR- Side squib RH (Front seat airbag assembly RH) P31-3 ICR- Curtain shield squib RH (Curtain shield airbag assembly RH) P31-4 ICR+ Curtain shield squib RH (Curtain shield airbag assembly RH) P31-5 PR+ Front pretensioner squib RH (Front seat outer belt assembly RH) P31-6 PR- Front pretensioner squib RH (Front seat outer belt assembly RH) P31-7*2 PRR- Rear pretensioner squib RH (Rear seat 3 point type outer belt assembly RH) P31-8*2 PRR+ Rear pretensioner squib RH (Rear seat 3 point type outer belt assembly RH) P31-9 FSR+ Occupant detection ECU P31-15*1 SRR- Rear side squib RH (Rear seat airbag assembly RH) P31-16*1 SRR+ Rear side squib RH (Rear seat airbag assembly RH) P31-17 FSR- Occupant detection ECU P31-23 BBR- Rear airbag sensor RH P31-24 BBR+ Rear airbag sensor RH K51-1 P2+ Front passenger side squib 2nd step (Instrument panel passenger airbag assembly) K51-2 P2- Front passenger side squib 2nd step (Instrument panel passenger airbag assembly) K51-3 P- Front passenger side squib (Instrument panel passenger airbag assembly) K51-4 P+ Front passenger side squib (Instrument panel passenger airbag assembly) K51-5 D+ Driver side squib (Horn button assembly) K51-6 D- Driver side squib (Horn button assembly) K51-7 D2- Driver side squib 2nd step (Horn button assembly) K51-8 D2+ Driver side squib 2nd step (Horn button assembly) K51-9 DK+ Driver side knee airbag squib (Lower No. 1 instrument panel airbag assembly) K51-10 DK- Driver side knee airbag squib (Lower No. 1 instrument panel airbag assembly) K51-13 CANH CAN communication line K51-17 P-AB Passenger airbag ON/OFF indicator (Air conditioning control assembly) K51-18 GSW Main body ECU (Multiplex network body ECU) K51-19 PK+ Front passenger side knee airbag squib (Lower No. 2 instrument panel airbag assembly) K51-20 PK- Front passenger side knee airbag squib (Lower No. 2 instrument panel airbag assembly) K51-21 IG2 A/BAG-IG2 fuse K51-22 CANL CAN communication line K51-23 PAON Passenger airbag ON/OFF indicator (Air conditioning control assembly) K51-24*3 GSW3 DCM (Telematics transceiver) K51-25 E1 Ground K51-26 E2 Ground K51-27 -SR Front airbag sensor RH K51-28 -SL Front airbag sensor LH K51-29 +SR Front airbag sensor RH K51-30 +SL Front airbag sensor LH Q9-1*2 PLR+ Rear pretensioner squib LH (Rear seat 3 point type outer belt assembly LH) Q9-2*2 PLR- Rear pretensioner squib LH (Rear seat 3 point type outer belt assembly LH) Q9-3 PL- Front pretensioner squib LH (Front seat outer belt assembly LH) Q9-4 PL+ Front pretensioner squib LH (Front seat outer belt assembly LH) Q9-5 ICL+ Curtain shield squib LH (Curtain shield airbag assembly LH) Q9-6 ICL- Curtain shield squib LH (Curtain shield airbag assembly LH) Q9-7 SFL- Side squib LH (Front seat airbag assembly LH) Q9-8 SFL+ Side squib LH (Front seat airbag assembly LH) Q9-9*1 SRL+ Rear side squib LH (Rear seat airbag assembly LH) Q9-10*1 SRL- Rear side squib LH (Rear seat airbag assembly LH) Q9-15 LBE+ Seat belt buckle switch LH (Front seat inner belt assembly LH) Q9-16 LSP+ Seat position airbag sensor Q9-17 BBL+ Rear airbag sensor LH Q9-18 BBL- Rear airbag sensor LH Q9-23 LBE- Seat belt buckle switch LH (Front seat inner belt assembly LH) Q9-24 LSP- Seat position airbag sensor *1: w/ Rear Seat Side Airbags *2: w/ Rear Pretensioners *3: w/ Manual (SOS) Switch

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1. CHECK DLC3 Check the DLC3. Refer to «GENERAL INFORMATION [04/2013 - ]»(ref-665529-S26412111322014102400000)
2. 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 diagnosis of the airbag system (including the seat belt pretensioners) is performed. HINT: If malfunctions are 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 airbag sensor assembly constantly monitors the airbag system for malfunctions. HINT: If malfunctions are detected during the constant check, the airbag sensor assembly will indicate the malfunction as follows: The SRS warning light comes on. The SRS warning light goes off, and then comes on. This 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 is malfunctioning: 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 the engine switch is turned from off to on (IG). HINT: The airbag sensor assembly keeps the SRS warning light on if airbags have been deployed.
3. 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 [04/2013 - ]»(ref-665792-S11364000012014102400000) The SRS warning light comes on occasionally after the primary check period. The SRS warning light comes on, but DTCs are not output. The engine switch is turned from off to on (IG), but the SRS warning light does not come on.
4. 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 indicate ON/OFF depending on the conditions listed below. INDICATOR OPERATION Front Passenger Seat Condition Passenger Airbag ON/OFF Indicator SRS Warning Light ON Indicator OFF Indicator Vacant OFF ON OFF Adult is seated ON OFF OFF Child is seated OFF ON OFF Child restraint system is installed Front passenger occupant classification failure OFF ON ON HINT: The passenger airbag ON/OFF indicator illuminates based on the timing chart below in order to check the indicator light circuit. When the occupant classification system is malfunctioning, both the SRS warning light and passenger airbag ON/OFF indicator ("OFF") come on. In this case, check the DTCs in the airbag system first.
5. 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 indicator operation table in the preceding step regarding the passenger airbag ON/OFF indicator when the engine switch is turned on (IG) and approximately 6 seconds elapse.
6. FUNCTION OF SRS CONNECTORS The SRS connectors are located as shown in the illustration. Connector Type Application Terminal Twin-lock Mechanism Connectors 2, 4, 6, 9, 10, 15, 16, 20, 22, 24, 28, 42 Half Connection Prevention Mechanism Connectors 6, 10, 16 Activation Prevention Mechanism Connectors 2, 4, 5, 7, 9, 11, 13, 31, 33, 35 Connector Lock Mechanism (1) Connectors 8, 12, 14, 34, 36 Connector Position Assurance Mechanism Connectors 18, 26, 30, 32 Connector Lock Mechanism (2) Connector A Improper Connection Prevention Lock Mechanism Connector A Terminal twin-lock mechanism This mechanism is designed to increase the ability of the terminal to remain connected and prevent it from accidentally being disconnected. The connector has a two-piece construction consisting of the housing and spacer to securely lock the terminal using both the lance (primary lock) and spacer (secondary lock). Half connection prevention mechanism This mechanism is designed to prevent the connector from being connected only halfway. If the connector is not completely connected, the connector is disconnected due to the spring force so that no continuity exists. Activation prevention mechanism This mechanism is designed to create a short circuit automatically between the positive and negative terminals of an airbag power source connector when disconnected. The short spring plate contained in the connector creates a closed circuit on the airbag side (no potential difference can occur between both terminals), preventing accidental airbag deployment when servicing. Connector lock mechanism (1) This mechanism is designed to prevent the connector from accidentally being disconnected. Locking the connector locking button engages the locking button claws in the grooves on the other side of the connector to connect the connector securely. Connector Position Assurance (CPA) mechanism This mechanism is designed to detect when the connector is connected only halfway. The CPA and female connector slide to the male connector side at the same time and the primary lock is completed when the female connector is engaged with the male connector. From this point, only the CPA slides to the male connector side and secondary lock is completed when the CPA retainer is engaged with the female connector. When the CPA and female connector ends are aligned, they are completely engaged. Connector lock mechanism (2) This mechanism is designed to prevent the connector from accidentally being disconnected. Sliding the connector all the way into the holder and locking the lance completes the primary lock. Engaging the retainer to the holder as shown in the illustration completes the secondary lock, preventing the connector from accidentally being disconnected. Improper connection prevention lock mechanism This mechanism is designed to prevent the connector from being connected only halfway. When the holder is connected to the airbag sensor assembly, the unlock rib unlocks the temporary hold lock, allowing the lever to be pushed in by rotating around axis A. Locking the lever to the holder locks the holder securely.
7. ACTIVATION PREVENTION MECHANISM Function of activation prevention mechanism An activation prevention mechanism is built into the connector (on the 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 (0.0197 in.)) between the terminals and 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 short spring from being damaged, always use a piece of paper with the same thickness as the male terminal.

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1. DTC CHECK (USING SST CHECK WIRE) Check for DTCs (Current trouble codes). Turn the engine switch on (IG), and wait for at least 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 for DTCs (History trouble codes). Turn the engine switch off. 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 at least 60 seconds. Read the DTCs. Read the blinking patterns of the DTCs. As an example, the blinking patterns for the normal system code and trouble codes 11 and 31 are shown in the illustration. Normal system code indication (without history trouble codes) The light blinks twice per second. Normal system code indication (with history trouble codes) When a history trouble code is stored in the airbag sensor assembly, the light blinks only once per second. Trouble code indication The first blink(s) indicate the first number of the DTC. The second blink(s) indicate the second number of the DTC and occur after a 1.5-second pause. NOTE: When a DTC includes a letter (such as DTC 8A), the light blinks 8 times and then blinks 10 times to indicate the A after a 1.5-second pause. COMPARISON TABLE Number of Blinks Indicated Letter 10 A 11 B 12 C 13 D 14 E 15 F 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 [04/2013 - ]»(ref-665868-S39036818392014102400000)
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 the engine switch off. In this case, proceed to the next procedure. 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 will come 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 wait for at least 60 seconds. Turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Trouble Codes. Body Electrical > SRS Airbag > Trouble Codes Check for 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 wait for at least 60 seconds. Turn the Techstream on. Enter the following menus: Body Electrical / SRS Airbag / Trouble Codes. Body Electrical > SRS Airbag > Clear DTCs Clear the DTCs by following the prompts on the Techstream screen. HINT: Refer to the Techstream operator's manual for further details.

DATA LIST / ACTIVE TEST [04/2013 - ]

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 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. Body Electrical > SRS Airbag > 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 is detected Forward/Bkward - Passenger Classification Passenger Classification NG: Data is not determined Child: Child is seated or vacant AF05: Adult is seated AM50: Adult is seated Fail: Failure is detected Child/AF05/AM50 - Left side Buckle SW Driver Side Buckle SW Unset: Seat belt is not fastened Set: Seat belt is fastened NG: Data is not determined Unset/Set - Right side Buckle SW Front Passenger Side Buckle SW Unset: Seat belt is not fastened Set: Seat belt is fastened NG: Data is not determined Unset/Set - Display Type Information Display Type Information LR: Display is indicated by LH/RH DP: Display is indicated by Driver/Passenger LR - Number of Past DTC Number of Past DTC Min.: 0, Max.: 255 0

DIAGNOSTIC TROUBLE CODE CHART [04/2013 - ]

AIRBAG SYSTEM

See also:
• DIAGNOSIS SYSTEM [04/2013 - ]