Page 636 of 2062
Downloaded from www.Manualslib.com manuals search engine DI0XN−01
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
Page 654 of 2062

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
Page 658 of 2062

Downloaded from www.Manualslib.com manuals search engine H18114
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
Page 660 of 2062

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
Page 662 of 2062
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
Page 664 of 2062

Downloaded from www.Manualslib.com manuals search engine N14677
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
Page 667 of 2062
Downloaded from www.Manualslib.com manuals search engine R15206
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
Page 668 of 2062
Downloaded from www.Manualslib.com manuals search engine AB0118AB0119W05587W05586AB0117H00347
ACC ON
or LOCK
w/o Tachometer
w/ Tachometer
AB0118
R14305AB0119
H00030
ACCON
or
E1
Tc
(+) (−)
DI−404
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
If DTC is not displayed, do following troubleshooting:
1 Does SRS warning light up for approx. 6 seconds?
PREPARATION:
Check operation of SRS warning light after ignition switch is
turned from LOCK position to ACC or ON position.
NO Check SRS warning light system (See page
DI−365).
YES
2 Check voltage between terminals Tc and E1 of DLC1.
PREPARATION:
Turn ignition switch to ACC or ON.
CHECK:
Measure voltage between terminals Tc and E1 of DLC1.
OK:
Voltage: 10 − 16 V
OK Go to step 4.
NG