Toyota Tundra. Manual — part 2636

f. Using the Techstream, check for DTCs of the occupant classification ECU (see DTC

CHECK/CLEAR ).

OK: DTC B1786 is not output.

HINT:

DTCs other than DTC B1786 may be output at this time, but they are not related to this check.

NG: Go to step 9

OK: END

9. REPLACE OCCUPANT CLASSIFICATION ECU

a. Turn the ignition switch OFF.

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

c. Replace the occupant classification ECU.



for Manual Seat (see FRONT SEAT ASSEMBLY (FOR FOLD DOWN SEAT TYPE) )



for Power Seat (see FRONT SEAT ASSEMBLY (FOR POWER SEAT) )

HINT:

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

10. PERFORM ZERO POINT CALIBRATION

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

b. Connect the Techstream to the DLC3.

c. Turn the ignition switch ON, and wait for at least 60 seconds.

d. Using the Techstream, perform the zero point calibration (see INITIALIZATION ).

11. PERFORM SENSITIVITY CHECK

a. Using the Techstream, perform the sensitivity check (see INITIALIZATION ).

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NEXT: END

DTC B1787: REAR OCCUPANT CLASSIFICATION SENSOR LH COLLISION DETECTION

DESCRIPTION

DTC B1787 is set when the occupant classification ECU receives a collision detection signal, which is sent by
the rear occupant detection sensor LH when an accident occurs.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

DTC B1787 is also set when the front seat frame with adjuster RH is subjected to a strong impact, even if an
actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in
a collision, DTC B1787 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1787 is output, first perform the zero point calibration and sensitivity check.

DTC TROUBLE DETECTION CONDITION TABLE

HINT:



When DTC B1650/32 is set as a result of troubleshooting the airbag system, perform troubleshooting for
DTC B1787 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

DTC

Code

DTC Detection Condition

Trouble Area

B1787

Either of following conditions is met:



Occupant classification ECU receives collision
detection signal, which is sent by rear occupant
detection sensor LH when accident occurs



Front seat frame with adjuster RH is subjected to
strong impact, even if actual accident has not
occurred



Front seat frame with adjuster
RH (Rear occupant detection
sensor LH)



Occupant classification ECU

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

Fig. 217: Identifying Rear Occupant Classification Sensor LH Collision Detection - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

1. CHECK FOR DTC

a. Turn the ignition switch ON, and wait for at least 60 seconds.

b. Clear any DTCs stored in the center airbag sensor (see DTC CHECK/CLEAR ).

c. Turn the ignition switch OFF.

d. Turn the ignition switch ON, and wait for at least 60 seconds.

e. Using the Techstream, check for DTCs of the occupant classification ECU (see DTC

CHECK/CLEAR ).

OK: DTC B1787 is not output.

HINT:

NOTE:

After the ignition switch is turned OFF, the navigation system requires
approximately 90 seconds to record various types of memory and settings. As a
result, after turning the ignition switch OFF, wait 90 seconds or more before
disconnecting the cable from the negative (-) battery terminal.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

DTCs other than DTC B1787 may be output at this time, but they are not related to this check.

NG: Go to step 2

OK: USE SIMULATION METHOD TO CHECK (See DIAGNOSIS SYSTEM )

2. PERFORM ZERO POINT CALIBRATION

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON, and wait for at least 60 seconds.

c. Using the Techstream, perform the zero point calibration (see INITIALIZATION ).

NG: Go to step 5

OK: Go to next step

3. PERFORM SENSITIVITY CHECK

a. Using the Techstream, perform the sensitivity check (see INITIALIZATION ).

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NG: Go to step 5

OK: Go to next step

4. CHECK FOR DTC

a. Turn the ignition switch ON, and wait for at least 60 seconds.

b. Clear any DTCs stored in the center airbag sensor (see DTC CHECK/CLEAR ).

c. Turn the ignition switch OFF.

d. Turn the ignition switch ON, and wait for at least 60 seconds.

e. Using the Techstream, check for DTCs of the occupant classification ECU (see DTC

CHECK/CLEAR ).

OK: DTC B1787 is not output.

HINT:

DTCs other than DTC B1787 may be output at this time, but they are not related to this check.

NG: Go to step 5

OK: END

5. REPLACE FRONT SEAT FRAME WITH ADJUSTER ASSEMBLY RH

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra