Toyota Sequoia (2005). Manual - part 381

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DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1319

1513

8

Replace occupant classification ECU.

(a)

Turn the ignition switch to the LOCK 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

9

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

10

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–1320

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1514

DTC

B1790

Airbag Sensor Assembly Communication
Circuit Malfunction

CIRCUIT DESCRIPTION

The airbag sensor assembly communication circuit consists of the occupant classification ECU and the air-
bag sensor assembly.
DTC B1790 is recorded when a malfunction is detected in the airbag sensor assembly communication cir-
cuit.

DTC No.

DTC Detecting Condition

Trouble Area

B1790

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 airbag

sensor assembly communication circuit for 2 seconds.

Airbag sensor assembly malfunction

Occupant classification ECU malfunction

Occupant classification ECU

Airbag sensor assembly

Floor wire

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 B1790 is output, perform troubleshooting
for the DTC.

DIDHD–01

H02750

O6
Occupant Classification ECU

FSR+

BL1

3

W

W

A21

16

Airbag Sensor Assembly

A21

24

B

B

BL1

5

FSR–

FSR+

FSR–

8

4

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1321

1515

WIRING DIAGRAM

DI–1322

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1516

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 B1790 is not output.

HINT:
Codes other than DTC B1790 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

).