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

1. Measure the voltage of the battery.

   Standard voltage

   11 to 14 V

NG → REPLACE BATTERY 

OK: Go to next step 

1. Check the ECU-B fuse.

   Standard resistance

   Below 1 Ω

NG → REPLACE FUSE 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 1: Identifying Wire Harness (Source Voltage) Connector Terminal Identification

   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 on (IG).
6. Measure the voltage and resistance according to the value(s) in the table below.

   Standard voltage and resistance

   for Power seat 

   for Manual seat 

   Tester connection	Condition	Specified condition
   T10-1 (+B) - Body ground	Always	10 to 14 V
   T10-3 (GND) - Body ground	Always	Below 1 Ω
   T10-7 (IG) - Body ground	Ignition switch on (IG)	10 to 14 V

   Tester connection	Condition	Specified condition
   O4-1 (+B) - Body ground	Always	10 to 14 V
   O4-3 (GND) - Body ground	Always	Below 1 Ω
   O4-7 (IG) - Body ground	Ignition switch on (IG)	10 to 14 V

NG → REPAIR OR REPLACE WIRE HARNESS 

OK: Go to next step 

1. Turn the ignition switch off.
2. Disconnect the negative (-) terminal cable from the battery.
3. Connect the connector to the occupant classification ECU.
4. Connect Techstream to the DLC3.
5. Connect the negative (-) terminal cable to the battery.
6. Turn the ignition switch on (IG).
7. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
8. for TMC made:

   Clear the DTCs stored in the center airbag sensor assembly. Refer to DTC CHECK / CLEAR .

9. except TMC made:

   Clear the DTCs stored in the center airbag sensor assembly. Refer to DTC CHECK / CLEAR .

10. Turn the ignition switch off.
11. Turn the ignition switch on (IG), and wait for at least 10 seconds.
12. Using Techstream, check the DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

    OK

    B1794 is not output.

    HINT: 

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

OK → See step   8 

NG: 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. Replace the occupant classification ECU. Refer to REMOVAL .

NEXT: Go to next step 

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

   OK

   "Zero Point Calibration is complete." is displayed.

NEXT: Go to next step 

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

   Standard value

   27 to 33 kg (59.52 to 72.75 lb)

NEXT → END