Toyota Sequoia (2005). Manual - part 380

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1315

1509

DTC

B1788

Occupant Classification Sensor Rear RH
Collision Detection

CIRCUIT DESCRIPTION

DTC B1788 is output when the occupant classification ECU receives a collision detection signal sent by the
occupant classification sensor rear RH if an accident occurs.
DTC B1788 is also output when the front seat assembly RH is subjected to a strong impact, even if an actual
accident does not occur.
However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is
not in a collision, DTC B1788 can be cleared by ”Zero point calibration” and ”Sensitivity check”.
Therefore, if DTC B1788 is output, first perform ”Zero point calibration” and ”Sensitivity check”.

DTC No.

DTC Detecting Condition

Trouble Area

B1788

Front seat assembly RH malfunction

Occupant classification ECU malfunction

Occupant classification sensor rear RH detects heavy

load.

Front seat assembly RH 

(Occupant classification sensor rear RH)

Occupant classification ECU

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 B1788 is output, perform troubleshooting
for the DTC.

WIRING DIAGRAM

See page 

DI–1290

.

INSPECTION PROCEDURE

1

Perform zero point calibration.

(a)

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch to the ON position.

(c)

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

DI–1128

).

OK:

The ”COMPLETED” is displayed.

NG

Go to step 4.

OK

DIDHC–01

DI–1316

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1510

2

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)

NG

Go to step 4.

OK

3

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 B1788 is not output.

HINT:
Codes other than DTC B1788 may be output at this time, but they are not related to this check.

NG

Go to step 4.

OK

END

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1317

1511

4

Replace front seat assembly RH.

(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 front seat assembly RH (see page 

BO–112

, 

BO–126

).

HINT:
Perform the inspection using parts from a normal vehicle if possible.

NEXT

5

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.

NG

Go to step 8.

OK

6

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)

NG

Go to step 8.

OK

DI–1318

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1512

7

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 B1788 is not output.

HINT:
Codes other than DTC B1788 may be output at this time, but they are not related to this check.

NG

Go to step 8.

OK

END