Occupant Classification System (Diagnostic Codes & Symptom Tests): Overview Toyota 4Runner V

DESCRIPTION

The passenger side buckle switch circuit consists of the occupant classification ECU and front seat inner belt RH.

DTC B1771 is stored when a malfunction is detected in the passenger side buckle switch circuit.

Troubleshoot DTC B1771 first when DTCs B1771 and B1795 are output simultaneously.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1771 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 18

The front occupant classification sensor LH circuit consists of the occupant classification ECU and front occupant classification sensor LH.

DTC B1780 is stored when a malfunction is detected in the front occupant classification sensor LH circuit.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1780 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 19

The front occupant classification sensor RH circuit consists of the occupant classification ECU and front occupant classification sensor RH.

DTC B1781 is stored when a malfunction is detected in the front occupant classification sensor RH circuit.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1781 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 20

The rear occupant classification sensor LH circuit consists of the occupant classification ECU and rear occupant classification sensor LH.

DTC B1782 is stored when a malfunction is detected in the rear occupant classification sensor LH circuit.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1782 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 21

The rear occupant classification sensor RH circuit consists of the occupant classification ECU and rear occupant classification sensor RH.

DTC B1783 is stored when a malfunction is detected in the rear occupant classification sensor RH circuit.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1783 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 22

DTC B1785 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the front occupant classification sensor LH when an accident occurs.

DTC B1785 is also stored when the separate type front seat cushion spring RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle has not been in a collision, DTC B1785 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1785 is output, first perform the zero point calibration and sensitivity check.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1785 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1786 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the front occupant classification sensor RH when an accident occurs.

DTC B1786 is also stored when the separate type front seat cushion spring RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle has not been in a collision, DTC B1786 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1786 is output, first perform the zero point calibration and sensitivity check.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1786 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1787 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the rear occupant classification sensor LH when an accident occurs.

DTC B1787 is also stored when the separate type front seat cushion spring RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle has not been in a collision, DTC B1787 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1787 is output, first perform the zero point calibration and sensitivity check.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1787 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1788 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the occupant classification sensor rear RH when an accident occurs.

DTC B1788 is also stored when the separate type front seat cushion spring RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle has not been in a collision, DTC B1788 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1788 is output, first perform the zero point calibration and sensitivity check.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1788 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

The center airbag sensor communication circuit consists of the occupant classification ECU and center airbag sensor.

DTC B1790 is stored when a malfunction is detected in the center airbag sensor communication circuit.

HINT

1. When DTC B1630/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1790 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 23

The occupant classification sensor power supply circuit consists of the occupant classification ECU and occupant classification sensors.

DTC B1793 is stored when a malfunction is detected in the occupant classification sensor power supply circuit.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1793 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 24

DTC B1794 is stored when a malfunction is detected in the occupant classification ECU.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 25

Scheme 26

1. CHECK FOR DTC Turn the ignition switch to ON, and wait for at least 60 seconds. Clear the DTCs stored in memory. Refer to «DTC CHECK / CLEAR»(ref-422257-S00628845952011092600000) . HINT: First clear the DTCs stored in the occupant classification ECU, and then clear the DTCs stored in the center airbag sensor. Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared. Turn the ignition switch off, and wait for at least 10 seconds. Turn the ignition switch to ON, and wait for at least 60 seconds. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(ref-422257-S00628845952011092600000) . OK DTC B1794 is not output. HINT: DTCs other than DTC B1794 may be output at this time, but they are not related to this check. NG --> See step 2 OK --> See step 9
2. CHECK CONNECTION OF CONNECTOR Turn the ignition switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Check that the connectors are properly connected to the center airbag sensor, occupant classification sensors and occupant classification ECU. OK Connectors are properly connected. NG --> CONNECT CONNECTOR OK: Go to next step
3. CHECK CONNECTOR Disconnect the connector from the occupant classification ECU. Check that the connectors (on the occupant classification ECU side) are not damaged. Refer to «ELECTRONIC CIRCUIT INSPECTION PROCEDURE»(ref-421949-S41663372572011092600000) . OK Connectors are not deformed or damaged. NG --> REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition a9-1 (+B) - Body ground Ignition switch ON 11 to 14 V a9-7 (IG2) - Body ground Turn the ignition switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition a9-3 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Occupant Classification ECU) NG --> REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK FOR DTC Connect the connectors to the occupant classification ECU. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds. Turn the ignition switch to ON, and wait for at least 60 seconds. Clear the DTCs stored in memory. Refer to «DTC CHECK / CLEAR»(ref-422257-S00628845952011092600000) . HINT: First clear the DTCs stored in the occupant classification ECU, and then clear the DTCs stored in the center airbag sensor. Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared. Turn the ignition switch off, and wait for at least 10 seconds. Turn the ignition switch to ON, and wait for at least 60 seconds. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(ref-422257-S00628845952011092600000) . OK DTC B1794 is not output. HINT: DTCs other than DTC B1794 may be output at this time, but they are not related to this check. NG --> See step 6 OK --> See step 9
6. REPLACE OCCUPANT CLASSIFICATION ECU Turn the ignition switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Replace the occupant classification ECU. Refer to «REMOVAL»(ref-422174-S25919481802011092600000) . HINT: Perform the inspection using parts from a normal vehicle when possible. NEXT: Go to next step
7. PERFORM ZERO POINT CALIBRATION Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds. Turn the ignition switch to ON, and wait for at least 60 seconds. Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(ref-422257-S39492386532011092600000) . OK "Zero Point Calibration is complete." is displayed. NEXT: Go to next step
8. PERFORM SENSITIVITY CHECK Using the Techstream, perform the sensitivity check. Refer to «INITIALIZATION»(ref-422257-S39492386532011092600000) . Standard Range 27 to 33 kg (59.5 to 72.8 lb) NEXT --> END
9. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(ref-422257-S37000505322011092600000)

DTC B1795 is stored when a malfunction is detected in the occupant classification ECU.

Troubleshoot DTC B1771 first when both DTCs B1771 and B1795 are present.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1795 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

During sleep mode, the occupant classification ECU monitors the condition of each sensor while the ignition switch is off. In this mode, if the occupant classification ECU detects an internal malfunction, DTC B1796 is stored.

HINT

1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1796 of the occupant classification system.
2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

The occupant classification system detects the front passenger seat condition. The system then informs the passenger of the front passenger airbag assembly and front passenger side knee airbag status (activated/not activated) with the passenger airbag ON/OFF indicator.

HINT

Approximately 6 seconds after the ignition switch is turned to ON, the passenger airbag ON/OFF indicator will indicate the on/off status depending on the conditions listed below.