Toyota Tundra. Manual — part 2628

NG: REPLACE FRONT SEAT WIRE RH

OK: Go to next step

5. CHECK FOR DTC

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

LH.

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

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

d. 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.

e. Turn the ignition switch OFF.

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

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

CHECK/CLEAR ).

OK: DTC B1780 is not output.

HINT:

DTCs other than DTC B1780 may be output at this time, but they are not related to this check.

NG: Go to step 6

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

6. 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) )

Y1-7 (SIG1) - Body ground

Y1-11 (SVC1) - Body ground

Y1-7 (SIG1) - Y1-11 (SVC1)

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

HINT:

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

7. 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 10

OK: Go to next step

8. 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 10

OK: Go to next step

9. CHECK FOR DTC

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

b. 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.

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 B1780 is not output.

HINT:

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

DTCs other than DTC B1780 may be output at this time, but they are not related to this check.

NG: Go to step 10

OK: END

10. 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.

11. PERFORM ZERO POINT CALIBRATION

a. Connect the Techstream to the DLC3.

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

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

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

12. 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 B1781: FRONT OCCUPANT CLASSIFICATION SENSOR RH CIRCUIT MALFUNCTION

DESCRIPTION

The front occupant detection sensor RH circuit consists of the occupant classification ECU and the front
occupant detection sensor RH.

DTC B1781 is set when a malfunction is detected in the front occupant detection sensor RH circuit.

DTC TROUBLE DETECTION CONDITION TABLE

DTC

Code

DTC Detection Condition

Trouble Area

One of following conditions is met:



Occupant classification ECU receives line short circuit



Front seat frame with
adjuster RH (Front

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra

HINT:



When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform
troubleshooting for DTC B1781 of the occupant classification system.



Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be
read.

WIRING DIAGRAM

Fig. 209: Identifying Front Occupant Classification Sensor RH Circuit Malfunction - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

B1781

signal, open circuit signal, short circuit to ground signal
or short circuit to +B signal in front occupant detection
sensor RH circuit for 2 seconds



Front occupant detection sensor RH malfunction



Occupant classification ECU malfunction

occupant detection sensor
RH)



Front seat wire RH



Occupant classification
ECU

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

2009 Toyota Tundra

2009 RESTRAINTS Supplemental Restraint System - Tundra