Toyota Sequoia (2005). Manual - part 366

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DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1259

1453

9

Replace occupant classification ECU.

(a)

Turn the ignition switch to the ON position.

(b)

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

(c)

Replace the occupant classification ECU (see page 

RS–111

).

NEXT

10

Perform zero point calibration.

(a)

Connect the negative (–) terminal cable to the battery.

(b)

Connect the hand–held tester to the DLC3.

(c)

Turn the ignition switch to the ON position.

(d)

Using the hand–held tester, perform ”Zero point calibration” (see page 

DI–1128

).

OK:

The ”COMPLETED” is displayed.

NEXT

11

Perform sensitivity check.

Using the hand–held tester, perform ”Sensitivity check” (see page 

DI–1128

).

OK:

Standard value: 27 to 33 kg (59.52 to 72.75 lb)

NEXT

END

DI–1260

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1454

DTC

B1780

Occupant Classification Sensor Front LH
Circuit Malfunction

CIRCUIT DESCRIPTION

The occupant classification sensor front LH circuit consists of the occupant classification ECU and the occu-
pant classification sensor front LH.
DTC B1780 is recorded when a malfunction is detected in the occupant classification sensor front LH circuit.

DTC No.

DTC Detecting Condition

Trouble Area

B1780

The occupant classification ECU receives a line short

circuit signal, an open circuit signal, a short circuit to

ground signal or a short circuit to B+ signal in the occu-

pant classification sensor front LH circuit for 2 seconds.

Occupant classification sensor front LH malfunction

Occupant classification ECU malfunction

Front seat assembly RH 

(Occupant classification sensor front LH)

Occupant classification ECU

Seat wire No. 1

HINT:
When DTC B1650/32 is detected as a result of troubleshooting for the supplemental restraint system, check
the DTCs stored in the occupant classification ECU. When DTC B1780 is output, perform troubleshooting
for the DTC.

DIDH5–01

H24040

Occupant
Classification ECU

O7

1

SGD1

O8
Occupant Classification 
Sensor Front LH

O7

7

SIG1

O7

11

SVC1

SGD1

SIG1

SVC1

3

2

1

O

G

V

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DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1261

1455

WIRING DIAGRAM

DI–1262

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1456

INSPECTION PROCEDURE

HINT:

If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installa-
tion bolts to see the under surface of seat cushion.

In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time
may cause a problem, such as seat rail deformation. Hold the seat only as necessary.

1

Check DTC.

CHECK:
(a)

Turn the ignition switch to the ON position.

(b)

Clear the DTCs stored in memory (see page 

DI–1147

).

HINT:
First clear DTCs stored in the occupant classification ECU and then in the airbag sensor assembly.
(c)

Turn the ignition switch to the LOCK position.

(d)

Turn the ignition switch to the ON position.

(e)

Using the hand–held tester, check the DTCs of the occupant classification ECU (see page 

DI–1147

).

OK:

DTC B1780 is not output.

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

NG

Go to step 2.

OK

From the results of the above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use the simulation method to check (see page 

DI–1137

).