sensor TOYOTA T100 1996 Factory Service Manual

Downloaded from www.Manualslib.com manuals search engine DI−390
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
DTC 15 Open in Front Airbag Sensor Circuit
CIRCUIT DESCRIPTION
The front airbag sensor detects the deceleration force in a frontal collision and is located in the front fender
on the left and right sides.
For details of the function of each component, see OPERATION on page RS−2.
DTC 15 is recorded when an open is detected in the front airbag sensor circuit.
NOTICE:
The front airbag sensor connector is equipped with an electrical connection check mechanism for
the purpose of detecting an open in the front airbag sensor (See page RS−2). This mechanism is
constructed so that when the terminals of the front airbag sensor have been connected (when the
connector housing lock is in the locked condition), the connection detection pin on the wire harness
side connects with the terminals for diagnosis use on the sensor side. If the connector is not properly
connected, the diagnosis system may detect only a malfunction code, even through the SRS is func-
tioning normally. When connecting the front airbag sensor connector, make sure it is connected
properly. If DTC 15 is displayed after the front airbag sensor connector has been connected, check
again that it is properly connected.
DTC No.DTC Detecting ConditionTrouble Area
15
Open cirxuit in +S wire harness or −S wire harness of front
airbag sensor.
Front airbag sensor malfunction.
Malfunction of electrical connection check mechanism of
front airbag sensor
Center airbag sensor assembly malfunction.
Front airbag sensor
Center airbag sensor
Wire harness
WIRING DIAGRAM
See page DI−373.
INSPECTION PROCEDURE
1 Preparaiton (See step 1 on page DI−396)
2 Check front airbag sensor circuit (Measure resistance between terminals +SR
and +SL of center airbag sensor assembly connector and body ground.) (See
step 2 on page DI−373).
NG Go to step 8.
OK
DI0XV−02

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ONAirbag Sensor Assembly
+SR
(−)−SR
(+)
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−391
1996 TOYOTA T100 (RM449U)
3 Check front airbag sensor circuit (Measure voltage between terminals +SR, +SL
of center airbag sensor assembly connector and body ground.).
PREPARATION:
(a) Connect negative (−) terminal cable to the battery, and
wait at least 2 seconds.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals +SR and body ground,
+SL and body ground of harness side connector of center air-
bag sensor assembly.
OK:
Voltage: 0 V
NG Repair or replace wire harness.
OK

Downloaded from www.Manualslib.com manuals search engine AB0118AB0119S08098H00316
H00350
H00340
Center Airbag
Sensor Assembly
D Squib
Spiral
Cable
ACC ON
or
DLC1
E1
Tc
Code 15
DI−392
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
4 Check center airbag sensor assembly.
PREPARATION:
(a) Connect center airbag assembly connector.
(b) Connect negative (−) terminal cable to battery, and wait
at least 2 seconds.
CHECK:
(a) Turn ignition switch to ACC or ON, and wait at least 20 se-
conds.
(b) Clear malfunction code stored in memory (See page
DI−365).
(c) Turn ignition switch to LOCK, and wait at least 20 se-
conds.
(d) Turn ignition switch to ACC or ON, and wait at least 20 se-
conds.
(e) Using SST, connect terminals Tc and E1 of DLC1.
SST 09843−18020
(f) Check DTC.
OK:
DTC 15 is not output.
HINT:
Codes other than code 15 may be output at this time, but they
are not relevant to this check.
NG Replace center airbag sensor assembly.
OK
From results of above inspection, malfunction part can now be considered normal.
To make sure of this, use simulation method to check.
5 Check connection of center airbag sensor assembly connector.
NG Repair.
OK

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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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Center Airbag
Sensor Assembly ON
ACC
IG2
(−)
(+)
DI−394
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
DTC 31 Center Airbag Sensor Assembly Malfunction
CIRCUIT DESCRIPTION
The center airbag sensor assembly consists of a center airbag sensor, safing sensor, drive circuit, diagnosis
circuit and ignition control, etc.
It receives signals from the airbag sensors, judges whether or not the SRS must be activated, and diagnosis
system malfunction.
DTC 31 is recorded when occurrence of a malfunction in the center airbag sensor assembly is detected.
DTC No.DTC Detecting ConditionTrouble Area
31Center airbag sensor assembly malfunctionCenter airbag sensor assembly
INSPECTION PROCEDURE
HINT:
When a malfunction code other than code 31 is displayed at the same time, first repair the malfunction indi-
cated by the malfunction code other than code 31.
1 Preparation (See step 1 on page DI−396)
2 Check voltage at IG2 and ACC of center airbag sensor assembly.
PREPARATION:
(a) Disconnect center airbag sensor assembly connector.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals IG2 and ACC of center air-
bag sensor assembly and body ground.
OK:
Voltage: Below 16 V
NG Check battery and charging system.
(3RZ−FE: See page CH−2)
(5VZ−FE: See page CH−1)
OK
DI0XW−02

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ACC ON
or
DLC1
E1
Tc
Code 31
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−395
1996 TOYOTA T100 (RM449U)
3 Is DTC 31 output again?
PREPARATION:
Clear malfunction code.
CHECK:
(a) Turn ignition switch to LOCK, and wait at least 20 se-
conds.
(b) Turn ignition switch to ACC or ON, and wait at least 20 se-
conds.
(c) Repeat operation in steps (a) and (b) at least 5 times.
(d) Using SST, connect terminals Tc and E1 of DLC1.
SST 09843−18020
(e) Check the DTC.
NO Using simulation method, reproduce malfunc-
tion symptoms (See page IN−16).
YES
Replace center airbag sensor assembly.

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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.