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

1. Measure the voltage of the battery.

   Voltage

   11 to 14 V

NG → REPLACE BATTERY 

OK: Go to next step 

1. Check the ECU-B fuse.

   Resistance

   Below 1 Ω

NG → REPLACE FUSE 

OK: Go to next step 

1. Turn the ignition switch to the LOCK position.
   Fig 1: Identifying O3 Occupant Classification ECU Connector Terminals

   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.
5. Turn the ignition switch to the ON position.
6. Measure the voltage and resistance according to the value(s) in the table below.

   Standard

   Tester connection	Condition	Specified condition
   O3-1 (+B) - Body ground	Ignition switch ON	10 to 14 V
   O3-7 (IG) - Body ground	Ignition switch ON	10 to 14 V
   O3-3 (GND) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE WIRE HARNESS 

OK: Go to next step 

1. Turn the ignition switch to the ON position.
2. Clear the DTCs stored in memory. Refer to 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.
4. Turn the ignition switch to the ON position, and wait for at least 10 seconds.
5. Using the Techstream, check the DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1794 is not output.

   HINT: 

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

NG → See step   5 

OK → USE SIMULATION METHOD TO CHECK 

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. Refer to REMOVAL .

   HINT: 

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

NEXT: Go to next step 

1. Connect the negative (-) terminal cable to the battery.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to the ON position.
4. Using the Techstream, perform the "Zero point calibration". Refer to INITIALIZATION .

   OK

   "Zero Point Calibration is complete." is displayed.

NEXT: Go to next step 

1. Using the Techstream, perform the "Sensitivity check". Refer to INITIALIZATION .

   Standard value

   27 to 33 kg (59.52 to 72.75 lb)

NEXT → END