B1794

SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: B1794: Open in Occupant Classification ECU Battery Positive Line
B1794 - Open in Occupant Classification ECU Battery Positive Line

DESCRIPTION

DTC B1794 is stored when a malfunction is detected in the occupant classification ECU battery positive line.





HINT
* When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 of the occupant classification system.
* Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

WIRING DIAGRAM





INSPECTION PROCEDURE

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

PROCEDURE

1. CHECK BATTERY

(a) Measure the voltage of the battery.

Standard voltage:

11 to 14 V

NG -- REPLACE BATTERY
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE)

(a) Turn the ignition switch off.





(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Disconnect the front seat wire RH connector from the floor wire.

(d) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(e) Turn the ignition switch to ON.

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

Standard Resistance:





Standard Voltage:





Text in Illustration





NG -- REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. CHECK FRONT SEAT WIRE RH (SOURCE VOLTAGE)

(a) Turn the ignition switch off.





(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Connect the front seat wire RH connector to the floor wire.

(d) Disconnect the occupant classification ECU connector.

(e) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(f) Turn the ignition switch to ON.

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

Standard Resistance:





Standard Voltage:





Text in Illustration





NG -- REPLACE FRONT SEAT WIRE RH Disassembly
OK -- Continue to next step.

4. CHECK FOR DTC

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Connect the connectors to the occupant classification ECU.

(d) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(e) Turn the ignition switch to ON, and wait for at least 60 seconds.

(f) Clear any DTCs stored in the memory Reading and Clearing Diagnostic Trouble Codes.

HINT
* First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
* Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

(g) Turn the ignition switch off.

(h) Turn the ignition switch to ON, and wait for at least 60 seconds.

(i) Using the Techstream, check for DTCs of the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.

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 -- REPLACE OCCUPANT CLASSIFICATION ECU

OK -- USE SIMULATION METHOD TO CHECK Diagnosis System

5. REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Replace the occupant classification ECU Removal.

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

NEXT -- Continue to next step.

6. PERFORM ZERO POINT CALIBRATION

(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Using the Techstream, perform the zero point calibration Programming and Relearning.

NEXT -- Continue to next step.

7. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check Programming and Relearning.

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NEXT -- END