Toyota Venza manuals

Toyota Venza: Open in Occupant Classification ECU Battery Positive Line (B1794)

Toyota Venza Service Manual / Supplemental Restraint Systems / Occupant Classification System / Open in Occupant Classification ECU Battery Positive Line (B1794)

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.

HINT:

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


CAUTION / NOTICE / HINT

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

2.

CHECK WIRE HARNESS (SOURCE VOLTAGE)

(a) Turn the ignition switch off.


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

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

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

(e) Turn the ignition switch to ON.

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

Standard Voltage:

for Power Seat

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

for Manual Seat

Tester Connection

Condition

Specified Condition

M14-1 (+B) - Body ground

Always

11 to 14 V

M14-7 (IG) - Body ground

Ignition switch ON

11 to 14 V

(g) Turn the ignition switch off.

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

Standard Resistance:

for Power Seat

Tester Connection

Condition

Specified Condition

S12-3 (GND) - Body ground

Always

Below 1 Ω

for Manual Seat

Tester Connection

Condition

Specified Condition

M14-3 (GND) - Body ground

Always

Below 1 Ω

Text in Illustration

*1

for Power Seat

*2

for Manual Seat

*3

Front view of wire harness connector

(to Occupant Classification ECU)


NG

REPLACE WIRE HARNESS


OK

3.

CHECK DTC

(a) Turn the ignition switch off.

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

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

(d) Connect the Techstream to the DLC3.

(e) Connect the cable to the negative (-) battery terminal.

(f) Turn the ignition switch to ON.

(g) Clear the DTCs stored in the occupant classification ECU (See page ).


(h) Clear the DTCs stored in the center airbag sensor assembly (See page ).


(i) Turn the ignition switch off.

(j) Turn the ignition switch to ON, and wait for at least 10 seconds.

(k) Using the Techstream, check for DTCs of the occupant classification ECU (See page ).


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.


OK

USE SIMULATION METHOD TO CHECK


NG

4.

REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

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

(c) Replace the occupant classification ECU (See page ).



NEXT

5.

PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Using the Techstream, perform Zero Point Calibration (See page ).


OK:

"Zero Point Calibration is complete." is displayed.


NEXT

6.

PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform Sensitivity Check (See page ).


Standard:

27 to 33 kg (59.5 to 72.8 lb)


NEXT

END

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