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 detection ECU auxiliary battery positive line.





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

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Service Precautions.

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

PROCEDURE

1. CHECK AUXILIARY BATTERY VOLTAGE

(a) Measure the voltage of the auxiliary battery.

Standard Voltage:

11 to 14 V

NG -- INSPECT AUXILIARY BATTERY Component Tests and General Diagnostics
OK -- Continue to next step.

2. CHECK WIRE HARNESS (SOURCE VOLTAGE)

(a) Turn the power switch off.





(b) Disconnect the cable from the negative (-) auxiliary battery terminal.

(c) Disconnect the connector from the occupant detection ECU.

(d) Connect the cable to the negative (-) auxiliary battery terminal.

(e) Turn the power switch on (IG).

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

Standard Voltage:





(g) Turn the power switch off.

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

Standard Resistance:





Text in Illustration





NG -- REPLACE WIRE HARNESS
OK -- Continue to next step.

3. CHECK DTC

(a) Turn the power switch off.

(b) Disconnect the cable from the negative (-) auxiliary battery terminal.

(c) Connect the connector to the occupant detection ECU.

(d) Connect the cable to the negative (-) auxiliary battery terminal.

(e) Turn the power switch on (IG).

(f) Clear the DTCs stored in the occupant detection ECU Reading and Clearing Diagnostic Trouble Codes.

(g) Clear the DTCs stored in the airbag sensor assembly Reading and Clearing Diagnostic Trouble Codes.

(h) Turn the power switch off.

(i) Turn the power switch on (IG), and wait for at least 10 seconds.

(j) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

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 -- REPLACE OCCUPANT DETECTION ECU

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

4. REPLACE OCCUPANT DETECTION ECU

(a) Turn the power switch off.

(b) Disconnect the cable from the negative (-) auxiliary battery terminal.

(c) Replace the occupant detection ECU Removal.

NEXT -- Continue to next step.

5. PERFORM ZERO POINT CALIBRATION

(a) Connect the cable to the negative (-) auxiliary battery terminal.

(b) Turn the power switch on (IG).

(c) Using the Techstream, perform Zero Point Calibration Programming and Relearning.

NEXT -- Continue to next step.

6. PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform Sensitivity Check Programming and Relearning.

NEXT -- END