Inspection Procedure

1. Turn the ignition switch to the on position.
2. Clear the DTCs stored in the memory (See DTC CHECK/CLEAR  ).

   HINT:

   First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.

3. Turn the ignition switch to the lock position, and wait for at least 10 seconds.
4. Turn the ignition switch to the on position.
5. Check the DTCs (See DTC CHECK/CLEAR  ).

   OK: DTC B1794 is not output. 

   HINT:

   DTCs other than B1794 may be output at this time, but they are not related to this check.

OK: USE SIMULATION METHOD TO CHECK 

NG: Go TO NEXT STEP 

1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the occupant classification ECU.

   OK: The connectors are properly connected. 

NG: CONNECT CONNECTORS 

OK: Go TO NEXT STEP 

1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Disconnect the Q4 connector from the occupant classification ECU.
   Fig 1: Identifying Q4 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Connect the negative (-) terminal cable to the battery.
5. Measure the voltage.

   Standard voltage 

   TESTER CONNECTION SPECIFIED CONDITION TABLE
   
   

   Tester Connection	Condition	Specified Condition
   Q4-1 (+B) - Body ground	Always	11 to 14 V
   Q4-7 (IG) - Body ground	Ignition switch on	11 to 14 V

6. Measure the resistance.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION TABLE
   
   

   Tester Connection	Condition	Specified Condition
   Q4-3 (GND) - Body ground	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - OCCUPANT CLASSIFICATION ECU) 

OK: Go TO NEXT STEP 

1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Connect the connectors to the occupant classification ECU.
4. Connect the negative (-) terminal cable to the battery.
5. Turn the ignition switch to the on position.
6. Clear any DTCs stored in the memory (See DTC CHECK/CLEAR  ).

   HINT:

   First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.

7. Turn the ignition switch to the lock position, and wait for at least 10 seconds.
8. Turn the ignition switch to the on position.
9. Using the intelligent tester, check for DTCs of the occupant classification ECU (See DTC CHECK/CLEAR  ).

   OK: DTC B1794 is not output. 

   HINT:

   DTCs other than B1794 may be output at this time, but they are not related to this check.

OK: USE SIMULATION METHOD TO CHECK 

NG: Go TO NEXT STEP 

1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the occupant classification ECU (See REMOVAL  ).

   HINT:

   Perform the inspection using parts from a normal vehicle when possible.

1. Connect the negative (-) terminal cable to the battery.
2. Connect the intelligent tester to the DLC3.
3. Turn the ignition switch to the on position.
4. Using the intelligent tester, perform the zero point calibration (See INITIALIZATION  ).

   OK: COMPLETED is displayed on the tester. 

1. Using the intelligent tester, perform the sensitivity check (See INITIALIZATION  ).
   1. Confirm that nothing is placed on the passenger seat.
   2. Confirm that the beginning sensor reading is within the standard range.

      Standard range: -3.2 to 3.2 kg (-7 to 7 lb) 

   3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.
   4. Confirm that the sensitivity is within the standard range.

      Standard range: 27 to 33 kg (59.52 to 72.75 lb) 

      HINT:

      When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).

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