1996 TOYOTA T100 warning light

Downloaded from www.Manualslib.com manuals search engine R15204
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

Downloaded from www.Manualslib.com manuals search engine H18115
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

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Airbag Sensor Assembly
LA
(−)
(+)ON
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−401
1996 TOYOTA T100 (RM449U)
3 Preparation. (See step 1 on page DI−396)
4 Check SRS warning light circuit.
PREPARATION:
(a) Connect negative (−) terminal cable to battery.
(b) Turn ignition switch to ACC or ON.
CHECK:
Measure voltage LA terminal of harness side connector of cen-
ter airbag sensor assembly and body ground.
OK:
Voltage: 10 − 16 V
NG Check SRS warning light bulb/repair SRS
warning light circuit.
OK

Downloaded from www.Manualslib.com manuals search engine AB0118AB0119W05587W05586
H00350
H00346
Center Airbag
Sensor Assembly
Spiral
CableD Squib
ACC ON
w/o Tachometer w/ Tachometeror
DI−402
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
5 Does SRS warning light come on?
PREPARATION:
(a) Disconnect negative (−) terminal cable from the battery.
(b) Connect center airbag sensor assembly connector.
(c) Connect negative (−) terminal cable to battery, and wait
at least 2 seconds.
(d) Turn ignition switch to ACC or ON.
CHECK:
Check operation of SRS warning light.
OK:
SRS warning light comes on.
NO Check terminal LA of center airbag sensor
assembly. If normal, 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.
6 Is new ECU−B fuse burnt out again?
NO Using simulation method, reproduce
malfunction symptoms. (See page IN−16)
YES
Check harness between ECU−B fuse and
SRS warning light.

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DLC1Tc IE111
Y−B6
EB
BR
E1
Y−BY−B 11
Short Connector8
Tc Center Airbag
Sensor Assembly
3
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−403
1996 TOYOTA T100 (RM449U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
By connecting terminal Tc and E1 of the DLC1, the airbag sensor assembly is set in the DTC output mode.
The DTCs are displayed by the blinking of the SRS warning light.
WIRING DIAGRAM
DI0Y1−02