Toyota Tundra. Manual — part 2634

HINT:



When DTC B1650/32 is set as a result of troubleshooting the airbag system, perform troubleshooting for
DTC B1785 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

Fig. 215: Identifying Front Occupant Classification Sensor LH Collision Detection Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

B1785



Occupant classification ECU receives collision
detection signal, which is sent by front 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 (Front occupant detection
sensor LH)



Occupant classification ECU

NOTE:

After the ignition switch is turned OFF, the navigation system requires

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

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 B1785 is not output.

HINT:

DTCs other than DTC B1785 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.

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

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 B1785 is not output.

HINT:

DTCs other than DTC B1785 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

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 front seat frame with adjuster RH (see FRONT POWER SEAT MOTOR

ASSEMBLY (FOR POWER SEAT) ).

HINT:

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

6. 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 ).

NG: Go to step 9

OK: Go to next step

7. 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 9

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

OK: Go to next step

8. CHECK FOR DTC

a. Connect the connectors to the occupant classification ECU and the front occupant detection sensor

LH.

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

c. Clear any DTCs stored in the memory (see DTC CHECK/CLEAR ).

HINT:



First clear DTCs stored in the occupant classification ECU and then in the center airbag
sensor.



Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the
DTCs cannot be cleared.

d. Turn the ignition switch OFF.

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

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

CHECK/CLEAR ).

OK: DTC B1785 is not output.

HINT:

DTCs other than DTC B1785 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.

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra