OCCUPANT CLASSIFICATION SYSTEM, Diagnostic DTC:B1794

DTC Code	DTC Name
B1794	Open in Occupant Classification ECU Battery Positive Line

DESCRIPTION

This circuit consists of the occupant classification ECU and power source circuit (battery, fuse and wire harness).

DTC B1794 is recorded when a malfunction is detected in the occupant classification ECU or power source circuit.

Tech Tips

If DTC B1794 is output after turning the ignition switch from off to ON and to off 50 times in a row when a malfunction occurs in the power circuit for the occupant classification system.

This DTC is output if a malfunction is detected even after being cleared unless the normal system code is input.

DTC No.	DTC Detection Condition	Trouble Area
B1794	The ignition switch is turned from off to ON, hold for 10 seconds or more, and turned off again 50 times in a row when a malfunction occurs in the power circuit for the occupant classification system. Occupant classification ECU malfunction	Battery ECU-B fuse Wire harness Occupant classification ECU

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1794 is output, perform troubleshooting for the DTC.

WIRING DIAGRAM

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

CHECK BATTERY
1. Measure the voltage of the battery.
  
  Standard Voltage
  
  11 to 14 V
NG
REPLACE BATTERY

OK

Standard Voltage
11 to 14 V

CHECK WIRE HARNESS (SOURCE VOLTAGE)

Text in Illustration

*1
Front view of wire harness connector

(to Occupant Classification ECU)

Turn the ignition switch off.
Disconnect the cable from the negative (-) battery terminal.
Disconnect the connector from the occupant classification ECU.
Connect the cable to the negative (-) battery terminal.
Turn the ignition switch to ON.

Text in Illustration
*1	Front view of wire harness connector (to Occupant Classification ECU)

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
S12-1 (+B) - Body ground	Always	11 to 14 V
S12-7 (IG) - Body ground	Ignition switch ON	11 to 14 V

Turn the ignition switch off.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
S12-3 (GND) - Body ground	Always	Below 1 Ω

REPLACE WIRE HARNESS

CHECK DTC
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal.
3. Connect the connector to the occupant classification ECU.
4. Connect the GTS to the DLC3.
5. Connect the cable to the negative (-) battery terminal.
6. Turn the ignition switch to ON.
7. Clear the DTCs stored in the occupant classification ECU Click here.
8. Clear the DTCs stored in the center airbag sensor assembly Click here.
9. Turn the ignition switch off.
10. Turn the ignition switch to ON, and wait for at least 10 seconds.
11. Using the GTS, check for DTCs of the occupant classification ECU Click here.
  
  OK
  
  DTC B1794 is not output.
  
  Tech Tips
  
  Codes other than DTC B1794 may be output at this time, but they are not related to this check.
NG
REPLACE OCCUPANT CLASSIFICATION ECU Click here

OK

USE SIMULATION METHOD TO CHECK Click here
REPLACE OCCUPANT CLASSIFICATION ECU
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal.
3. Replace the occupant classification ECU Click here.
NEXT
PERFORM ZERO POINT CALIBRATION
1. Connect the cable to the negative (-) battery terminal.
2. Connect the GTS to the DLC3.
3. Turn the ignition switch to ON.
4. Using the GTS, perform Zero Point Calibration Click here.
  
  OK
  
  "Zero Point Calibration is complete." is displayed.
NEXT
PERFORM SENSITIVITY CHECK
1. Using the GTS, perform Sensitivity Check Click here.
  
  Standard
  
  27 to 33 kg (59.5 to 72.8 lb)
NEXT

END