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, and wire harness).
DTC B1794 is recorded when a malfunction is detected in the occupant classification ECU or the power source circuit.
HINT: If DTC B1794 is output after switching the power switch off-on (IG)-off 50 times in a row when a malfunction occurs in the power circuit for the occupant classification system, the DTC is output again.
This DTC is output when a malfunction is detected even after being cleared unless the normal system code is input.





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 (SOURCE VOLTAGE)




(a) Turn the power switch off.
(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 power switch on (IG).
(f) Measure the voltage and resistance according to the value(s) in the table below.
Standard voltage and resistance:
for Power seat
for Manual seat










NG -- REPAIR OR REPLACE WIRE HARNESS
OK -- Continue to next step.
4. CHECK DTC
(a) Turn the power switch off.
(b) Disconnect the negative (-) terminal cable from the battery.
(c) Connect the connector to the occupant classification ECU.
(d) Connect Techstream to the DLC3.
(e) Connect the negative (-) terminal cable to the battery.
(f) Turn the power switch on (IG).
(g) Clear the DTCs stored in the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.
(h) Clear the DTCs stored in the center airbag sensor assembly DTC Check / Clear.
(i) Turn the power switch off.
(j) Turn the power switch on (IG), and wait for at least 10 seconds.
(k) Using Techstream, check the DTCs of the occupant classification ECU Reading and Clearing Diagnostic Trouble Codes.
OK:
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 -- USE SIMULATION METHOD TO CHECK
OK -- Continue to next step.
5. REPLACE OCCUPANT CLASSIFICATION ECU
(a) Turn the power switch off.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the occupant classification ECU Removal.
NEXT -- Continue to next step.
6. PERFORM ZERO POINT CALIBRATION
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Using Techstream, perform the "zero point calibration" Programming and Relearning.
OK:
"Zero Point Calibration is complete." is displayed.
NEXT -- Continue to next step.
7. PERFORM SENSITIVITY CHECK
(a) Using Techstream, perform the "sensitivity check" Programming and Relearning.
Standard value:
27 to 33 kg (59.52 to 72.75 lb)
NEXT -- END