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Occupant Classification System (Diagnostics - Introduction): Diagnosis Lexus IS III

Airbag 3 illustrations ~1211 words

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.
SymptomSuspected AreaLink
The passenger airbag ON/OFF indicator indication differs from the indication patterns of "Indicator Operation". Refer to DIAGNOSIS SYSTEM [04/2013 - ]Trouble in passenger airbag ON/OFF indicatorRefer to Trouble in Passenger Airbag ON/OFF Indicator [04/2013 - ]

OCCUPANT CLASSIFICATION SYSTEM

Scheme 1

Scheme 1: TERMINALS OF ECU [04/2013 - ]
Scheme 1: TERMINALS OF ECU [04/2013 - ]
  1. OCCUPANT DETECTION ECU Terminal No. (Symbol) Wiring Color Terminal Description Condition Specification a14-1 (+B) - a14-3 (GND) W - W-B Battery Always 11 to 14 V a14-2 (DIA) GR Diagnosis (DLC3) -* -* a14-3 (GND) - Body ground W-B - Body ground Ground Always Below 1 V a14-4 (FSR-) - a14-3 (GND) LG - W-B Airbag sensor assembly communication line Always Below 1 V a14-5 (BGND) - a14-3 (GND) P - W-B Passenger side buckle switch ground line Always Below 1 V a14-6 (IG2) - a14-3 (GND) B - W-B Power source Engine switch on (IG) 11 to 14 V a14-7 (FSR+) - a14-4 (FSR-) L - LG Airbag sensor assembly communication line Engine switch on (IG) Pulse generation a14-8 (BSW) - a14-5 (BGND) G - P Passenger side buckle switch line Always Pulse generation a13-1 (SVC1) - a13-5 (SGD1) R - G Front occupant classification sensor LH power supply line Engine switch on (IG) 4.9 to 5.1 V a13-2 (SVC3) - a13-6 (SGD3) GR - W Rear occupant classification sensor LH power supply line Engine switch on (IG) 4.9 to 5.1 V a13-3 (SIG1) - a13-5 (SGD1) P - G Front occupant classification sensor LH signal line Engine switch on (IG) Pulse generation a13-4 (SIG3) - a13-6 (SGD3) SB - W Rear occupant classification sensor LH signal line Engine switch on (IG) Pulse generation a13-5 (SGD1) - a14-3 (GND) G - W-B Front occupant classification sensor LH ground line Always Below 1 V a13-6 (SGD3) - a14-3 (GND) W - W-B Rear occupant classification sensor LH ground line Always Below 1 V HINT: *: As this is a line that is connected to other systems, voltage changes according to the systems that are connected.

Scheme 2

Scheme 2: DIAGNOSIS SYSTEM [04/2013 - ]
Scheme 2: DIAGNOSIS SYSTEM [04/2013 - ]

Scheme 3

Scheme 3
Scheme 3
  1. CHECK DLC3 Check the DLC3. Refer to «GENERAL INFORMATION [04/2013 - ]»(ref-665529-S26412111322014102400000)
  2. 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 Occupant classification system 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 has a malfunction, 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.
  3. CHECK PASSENGER AIRBAG ON/OFF INDICATOR 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.

DTC CHECK/CLEAR [04/2013 - ]

  1. DTC CHECK Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG), and wait for at least 10 seconds. Turn the Techstream on. Enter the following menus: Body Electrical / Occupant Detection / Trouble Code. Body Electrical > Occupant Detection > Trouble Codes Check for DTCs by following the prompts on the Techstream screen. HINT: Refer to the Techstream operator's manual for further details.
  2. DTC CLEAR Turn the engine switch off. Connect the Techstream to the DLC3. Turn the engine switch on (IG), and wait for at least 10 seconds. Turn the Techstream on. Enter the following menus: Body Electrical / Occupant Detection / Trouble Code. Body Electrical > Occupant Detection > 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 - ]

  1. DATA LIST 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. 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 / Occupant Detection / Data List. Check the values by referring to the table below. Body Electrical > Occupant Detection > Data List Tester Display Measurement Item Range Normal Condition Diagnostic Note IG Switch Engine switch condition ON: Engine switch on (IG) OFF: Engine switch off ON/OFF - Passenger Buckle SW Passenger side buckle switch Set: The seat belt is fastened Unset: The seat belt is not fastened NG: Data is not determined Set/Unset - Passenger Classification Passenger classification AM50: Adult is seated AF05: Adult is seated Child: Child is seated CRS: Child restraint system is installed OFF: Vacant AM50/AF05/Child/CRS/OFF - Sensor Range Info Sensor range information OK: Always OK As sensor range is not set, OK is always displayed FL Sensor Range Info Front left sensor range information OK: Always OK As front left sensor range is not set, OK is always displayed RL Sensor Range Info Rear left sensor range information OK: Always OK As rear left sensor range is not set, OK is always displayed FL Sensor Voltage Front left sensor voltage Min.: 0.000 V Max.: 19.800 V 0.000 to 5.000 V - RL Sensor Voltage Rear left sensor voltage Min.: 0.000 V Max.: 19.800 V 0.000 to 5.000 V - FL Sensor Weight Info Front left sensor weight information Min.: -10.00 kg (-22.05 lb) Max.: 20.00 kg (44.09 lb) -10.00 to 20.00 kg (-22.05 to 44.09 lb) - RL Sensor Weight Info Rear left sensor weight information Min.: -10.00 kg (-22.05 lb) Max.: 30.00 kg (66.13 lb) -10.00 to 30.00 kg (-22.05 to 66.13 lb) - Total Weight Information Total weight information Min.: -40.00 kg (-88.19 lb) Max.: 100.00 kg (220.46 lb) -40.00 to 100.00 kg (-88.19 to 220.46 lb) - Number of Present DTC Number of present DTC recorded Min.: 0, Max.: 255 0 - Number of Past DTC Number of past DTC recorded Min.: 0, Max.: 255 0

DIAGNOSTIC TROUBLE CODE TABLE [04/2013 - ]

DTC No.Detection ItemLink
B1771Passenger Side Buckle Switch Circuit MalfunctionRefer to DTC B1771: Passenger Side Buckle Switch Circuit Malfunction [04/2013 - ]
B1780Front Occupant Classification Sensor LH Circuit MalfunctionRefer to DTC B1780: Front Occupant Classification Sensor LH Circuit Malfunction [04/2013 - ]
B1782Rear Occupant Classification Sensor LH Circuit MalfunctionRefer to DTC B1782: Rear Occupant Classification Sensor LH Circuit Malfunction [04/2013 - ]
B1785Front Occupant Classification Sensor LH Collision DetectionRefer to DTC B1785: Front Occupant Classification Sensor LH Collision Detection [04/2013 - ]
B1787Rear Occupant Classification Sensor LH Collision DetectionRefer to DTC B1787: Rear Occupant Classification Sensor LH Collision Detection [04/2013 - ]
B1790Center Airbag Sensor Assembly Communication Circuit MalfunctionRefer to DTC B1790: Center Airbag Sensor Assembly Communication Circuit Malfunction [04/2013 - ]
B1793Occupant Classification Sensor Power Supply Circuit MalfunctionRefer to DTC B1793: Occupant Classification Sensor Power Supply Circuit Malfunction [04/2013 - ]
B1794Open in Occupant Classification ECU Battery Positive LineRefer to DTC B1794: Open in Occupant Classification ECU Battery Positive Line [04/2013 - ]
B1795Occupant Classification ECU MalfunctionRefer to DTC B1795: Occupant Classification ECU Malfunction [04/2013 - ]
B1796Sleep Operation Failure of Occupant Classification ECURefer to DTC B1796: Sleep Operation Failure of Occupant Classification ECU [04/2013 - ]

OCCUPANT CLASSIFICATION SYSTEM

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