light TOYOTA T100 1996 Factory Manual Online

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− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−369
1996 TOYOTA T100 (RM449U)
DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the table
below (Proceed to the page given for that circuit.).
DTC No.
(See Page)Detection ItemTrouble AreaSRS
Warning Light
Normal
(DI−396)System normal−OFF
Source voltage dropBattery
Center airbag sensor assemblyON
11
(DI−373)
Short in squib circuit or front airbag
sensor circuit (to ground)Steering wheel pad (D squib)
Front airbag sensor
Spiral cable
Center airbag sensor assembly
Wire harness
ON
12
(DI−379)
Short in squib circuit or front airbag
sensor circuit (to B+)Steering wheel pad (D squib)
Front airbag sensor
Spiral cable
Center airbag sensor assembly
Wire harness
ON
14
(DI−385)
Open in D squib circuitSteering wheel pad (D squib)
Spiral cable
Center airbag sensor assembly
Wire harness
ON
15
(DI−390)Open in front airbag sensor circuitFront airbag sensor
Center airbag sensor assembly
Wire harness
ON
31
(DI−394)
Center airbag sensor assembly
malfunctionCenter airbag sensor assembly
ON
HINT:
When the SRS warning light remains lit up and the DTC is the normal code, this means a source voltage
drop. This malfunction is not stored in memory by the center airbag sensor assembly and if the power
source voltage returns to normal, approx. 10 seconds the SRS warning light will automatically go out.
When 2 or more codes are indicated, the lowest numbered code will apper first.
If a code not listed on the chart is displayed, the center airbag sensor assembly is faulty.

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R12499
Front Airbag Sensor RH
Front Airbag Sensor LH
Junction Block No.1
Center Airbag Sensor Assembly Spiral CableSRS Warning Light
Steering Wheel Pad
(with Airbag)
DI−370
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
PARTS LOCATION

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W02759
43 21
10 9 8 7 56 B A
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−371
1996 TOYOTA T100 (RM449U)
TERMINALS OF ECU
No.SymbolTerminal Name
A−Electrical Connection Check Mechanism
B−Electrical Connection Check Mechanism
1LASRS Warning Light
2D−Squib  (Driver)
3D+Squib  (Driver)
4TCDiagnosis
5E2Ground
6E1Ground
7+SRFront Airbag Sensor RH 
8+SLFront Airbag Sensor LH 
9IG2Power Source (IGN Fuse)
10ACCPower Source (CIG Fuse)

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DI−372
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
PROBLEM SYMPTOMS TABLE
Proceed with troubleshooting of each circuit in the table below.
SymptomSuspect AreaSee page
With the ignition switch at ACC or ON, the SRS warning light
sometimes lights up after approx. 6 seconds have elapsed.
SRS warning light is always lit up even when ignition switch is in
the LOCK position.
SRS warning light circuit
(Always lit up when ignition switch is in LOCK position.)DI−398
With the ignition switch at ACC or ON, the SRS warning lights
does not light up.SRS warning light circuit
(Does not light up when ignition switch is turned to ACC
or ON.)
DI−400
DTC not displayed.
SRS warning light is always lit up a DTC check procedure.
DTC displayed without Tc and E1 terminal connection.
Tc terminal circuitDI−403

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Center Airbag Sensor Assembly
(−)(+) +SL +SR
1
Front Airbag Sensor
+SR
+SL
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−393
1996 TOYOTA T100 (RM449U)
6 Check front airbag sensor (See step 6 on page DI−373).
NG Replace front airbag sensor.
OK
7 Check harness between center airbag sensor assembly and front airbag sensor.
PREPARATION:
(a) Disconnect center airbag sensor assembly connector.
(b) Using service wires, connect +SR, +SL and body ground
on the wire harness side of the center airbag sensor as-
sembly.
CHECK:
Measure resistance between terminal +SR, +SL and body
ground of front airbag sensor connector.
OK:
Resistance: Less than 1 Ω
NOTICE:
Lightly touch ohmmeter probes at position shown in il-
lustration.
NG Repair or replace wire harness.
OK
8 Check front airbag sensor circuit (Measure voltage between terminals +SR, +SL
of center airbag sensor assembly connector and body ground.) (See step 3).
NG Repair or replace wire harness.
OK
From results of above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use the simulation method to check.

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J/B No.1
Center Airbag
Sensor Assembly Ignition
SwitchShort
Connector Integration
Relay
R/B No.2
BatteryGR−RGR−R
B−YB−YACC
IG2
R−L
B−R L−R
CIG
IGN
ALT
AM1
AM2
WW
W
W
W−R
1A
1A 1CIA3
IA3
W−R34
34
16
15
17 3 4
7 2
83 14
8 2
2
2 2 2 26
4
2 5
13 DI−396
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
DTC Normal Source Voltage Drop
CIRCUIT DESCRIPTION
The SRS is equipped with a voltage−increase circuit (DC−DC converter) in the center airbag sensor assem-
bly in case the source voltage drops.
When the battery voltage drops, the voltage−increase circuit (DC−DC converter) functions to increase the
voltage of the SRS to normal voltage.
The diagnosis system malfunction display for this circuit is different to other circuits−when the SRS warning
light remains lit up and the DTC is a normal code, source voltage drop is indicated.
Malfunction in this circuit is not recorded in the center airbag sensor assembly, and the source voltage re-
turns to normal, after approx. 10 seconds the SRS warning light automatically goes off.
DTC No.Diagnosis
(Normal)Source voltage drop
WIRING DIAGRAM
DI989−01

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ONAirbag Sensor Assembly
IG
2Acc
(+) (−)
AB0119AB0234H00351
ON
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−397
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
1 Preparation.
PREPARATION:
(a) Turn ignition switch to LOCK.
(b) Disconnect center airbag sensor assembly connector.
(c) Turn ignition switch ON. But do not start engine.
(d) Measure voltage between terminal IG
2 or ACC on con-
nector wire harness side of center airbag sensor assem-
bly and body ground, and operate electric system (defog-
ger, wiper, headlight, heater blower, etc.).
Voltage: 6 V − 11.5 V at IG
2 and ACC
(e) Turn electric system switch OFF.
(f) Turn ignition switch to LOCK.
(g) Remove voltmeter and connect center airbag sensor as-
sembly connector.
2 Does SRS warning light turn off?
PREPARATION:
(a) Turn ignition switch to LOCK.
(b) Connect steering wheel pad connector.
(c) Connect center airbag sensor assembly connector.
(d) Turn ignition switch ON.
CHECK:
Operate electric system (defogger, wiper, headlight, heater
blower, etc.), and check that SRS warning light goes off.
NO Check for DTCs. If a DTC is output, perform trou-
bleshooting for DTC. If a normal code is output,
replace center airbag sensor assembly.
YES
From results of above inspection, malfunctioning part can now be considered normal. To make
sure of this, use simulation method to check.

Downloaded from www.Manualslib.com manuals search engine R15207
Center Airbag
Sensor Assembly
Relay Block
No.2
ECU−B SRS Warning Light
Battery
Short
ConnectorY−B Y−B
P−B P−B
P−B P−B Y−B
P−B
DLC1
TC
LA Tc
ABIE1
IE2
IA3 W
WYR
ALT
7
21211 2
2 1
2
58 6
8
5 11
22 11 DI−398
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
SRS Warning Light Circuit Malfunction (Always lit up, when
ignition switch is in LOCK position.)
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the SRS is normal, the SRS warning light lights up for approx. 6 seconds after the ignition switch is
turned from LOCK position to ACC or ON position, and then turns off automatically.
If there is a malfunction in the SRS, the SRS warning light lights up to inform the driver of the abnormality.
When terminals Tc and E1 of the DLC1 are connected, the DTC is displayed by the blinking of the SRS warn-
ing light.
WIRING DIAGRAM
DI98A−01

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LOCK
Center Airbag
Sensor Assembly
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−399
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
1 Does SRS warning light turn off?
PREPARATION:
(a) Turn ignition switch to LOCK.
(b) Disconnect negative (−) terminal cable from the battery,
and wait at least 90 seconds.
(c) Disconnect center airbag sensor assembly connector.
(d) Connect negative (−) terminal cable to battery.
CHECK:
Check operation of SRS warning light.
NO Check SRS warning light circuit or terminal AB
circuit of DLC1.
YES
Replace center airbag sensor assembly.

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Fuse
DI−400
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
SRS Warning Light Circuit Malfunction (Does not light up, when
ignition switch is turned to ACC or ON.)
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the SRS is normal, the SRS warning light lights up for approx. 6 seconds after the ignition switch is
turned from LOCK position to ACC or ON position, and then turns off automatically.
If there is a malfunction in the SRS, the SRS warning light lights up to inform the driver of the abnormality
When terminal Tc and E1 of the DLC1 are connected, the DTC is displayed by the blinking of the SRS warn-
ing light.
WIRING DIAGRAM
See page DI−398.
INSPECTION PROCEDURE
1 Check ECU−B Fuse.
PREPARATION:
Remove ECU−B fuse.
CHECK:
Check continuity of ECU−B fuse.
OK:
Continuity
HINT:
Fuse may be burnt out even if it appears to be OK during
visual inspection.
If fuse is OK, install it.
NG Go to step 6.
OK
2 Check connection of center airbag sensor assembly connector.
NG Repair.
OK
DI98B−01