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. Measure the resistance of the ECU-B No. 1 fuse.

   Standard resistance

   Below 1 Ω

NG → REPLACE FUSE 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 1: Checking Wire Harness (Source Voltage)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the negative (-) terminal cable from the battery.
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 according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   a3-1 (+B) - Body ground	Always	11 to 14 V
   a3-7 (IG) - Body ground	Ignition switch on (IG)	11 to 14 V

7. Turn the ignition switch off.
8. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Switch Condition	Specified Condition
   a3-3 (GND) - Body ground	Always	Below 1 Ω

NG → 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. Clear the DTCs stored in the center airbag sensor assembly. Refer to DTC CHECK / CLEAR .
9. Turn the ignition switch off.
10. Turn the ignition switch on (IG), and wait for at least 10 seconds.
11. Check for DTCs. Refer to DTC CHECK / CLEAR .

    OK

    DTC B1794 is not output.

    HINT: 

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

NG → See step   5 

OK → See step   8 

1. Turn the ignition switch off.
2. Disconnect the negative (-) terminal cable from the battery.
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 "zero point calibration". Refer to INITIALIZATION .

   OK

   "Zero Point Calibration is complete." is displayed.

NEXT: Go to next step 

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

   Standard

   27 to 33 kg (59.52 to 72.75 lb)

NEXT → END