B1794

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

DTC B1794 - Open in Occupant Classification ECU Battery Positive Line

DESCRIPTION

This circuit consists of the occupant classification ECU and the power source circuit (battery, fuse, wire harness).
DTC B1794 is recorded when a malfunction is detected in the occupant classification ECU or the power source circuit.
HINT: When DTC B1794 is output after switching the ignition switch LOCK-ON-LOCK 50 times in a row when a malfunction occurs in the power circuit for the occupant classification system, the DTC is output again when a malfunction is detected even once after being cleared, unless the normal system code is input.





HINT: When DTC B1150/23 is detected as a result of troubleshooting for Airbag System, check the DTCs stored in the occupant classification ECU. When DTC B1795 is output, perform troubleshooting for the DTC.

WIRING DIAGRAM





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 FUSE
(a) Check the ECU-B fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. CHECK WIRE HARNESS





(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Disconnect the connector from the occupant classification ECU.
(d) Connect the negative (-) terminal cable to the battery.
(e) Turn the ignition switch to the ON position.
(f) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(g) Turn the ignition switch to the LOCK position.
(h) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE WIRE HARNESS
OK -- Continue to next step.
4. CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in the occupant classification ECU .
(c) Clear the DTCs stored in the center airbag sensor assembly .
(d) Turn the ignition switch to the LOCK position.
(e) Turn the ignition switch to the ON position, and wait for at least 10 seconds.
(f) Check the DTCs .
OK:
DTC B1794 is not output.
HINT: Codes other than code B1794 may be output at this time, but they are not related to this check.

OK -- USE SIMULATION METHOD TO CHECK
NG -- Continue to next step.
5. REPLACE OCCUPANT CLASSIFICATION ECU
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the occupant classification ECU .
NEXT -- Continue to next step.
6. PERFORM ZERO POINT CALIBRATION
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the intelligent tester to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the intelligent tester, perform the "Zero point calibration" .
OK:
The "COMPLETED" is displayed.
NEXT -- Continue to next step.
7. PERFORM SENSITIVITY CHECK
(a) Using the intelligent tester, perform the "Sensitivity check" .
Standard value:
27 to 33 kg (59.52 to 72.75 lb)
NEXT -- END