DTC B1794: Open in Occupant Classification ECU Battery Positive Line: Procedure

1. Turn the ignition switch ON, and wait for at least 60 seconds.
2. Clear any DTCs stored in the memory. Refer to DTC CHECK / CLEAR .

   HINT: 

   • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
   • Use a Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
3. Turn the ignition switch off, and wait for at least 10 seconds.
4. Turn the ignition switch ON, and wait for at least 60 seconds.
5. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

   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 

1. Turn the ignition switch off.
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 center airbag sensor, occupant classification sensors and occupant classification ECU.

   OK

   Connectors are properly connected.

NG → CONNECT CONNECTOR 

OK: Go to next step 

1. Check that the connectors (on the occupant classification ECU side) are not damaged. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

   OK

   Connectors are not deformed or damaged.

NG → REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 1: Measuring Resistance Of Identifying L27 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Disconnect the connector from the occupant classification ECU.
4. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
5. Turn the ignition switch ON, and wait for at least 60 seconds.
6. Measure the resistance and voltage according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   L27-3 (GND) - Body ground	Always	Below 1 Ω

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   L27-1 (+B) - Body ground	Ignition switch ON	11 to 14 V
   L27-7 (IG) - Body ground

NG → REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Turn the ignition switch off.
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, and wait for at least 2 seconds.
5. Turn the ignition switch ON, and wait for at least 60 seconds.
6. Clear any DTCs stored in the memory. Refer to DTC CHECK / CLEAR .

   HINT: 

   • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
   • Use a Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
7. Turn the ignition switch off, and wait for at least 10 seconds.
8. Turn the ignition switch ON, and wait for at least 60 seconds.
9. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

   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 

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

   HINT: 

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

NEXT: Go to next step 

1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
2. Connect a Techstream to the DLC3.
3. Turn the ignition switch ON, and wait for at least 60 seconds.
4. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .

NEXT: Go to next step 

1. Using a Techstream, perform the sensitivity check. Refer to INITIALIZATION .

   Standard range

   27 to 33 kg (59.5 to 72.8 lb)

NEXT → END