1995 TOYOTA SUPRA warning light

Diagnostic trouble code clearance
Using diagnosis check wire:
(a) Connect the 2 service wires to terminals Tc and AB of DLC1
or DLC2.
(b) Turn the ignition switch to ACC or ON and wait approx. 6
seconds.
(c) Starting with the Tc terminal, apply body ground alternately
to terminal Tc and terminal AB twice each in cycles of 1.0
seconds. Confirm that body ground is absolute. Finally, keep
applying body ground to terminal Tc.
HINT: When alternately grounding terminals Tc and AB, re-
lease ground from one terminal and immediately apply it to
the other terminal within an interval of 0.2 second. If diagnos-
tic trouble codes do not clear, repeat the above procedure un-
til the codes are cleared.
(d) Several seconds after doing the clearing procedure, the SRS
warning light will blink in a 50 m sec. cycle to indicate the
codes have been cleared.
Using TOYOTA hand±held tester:
(a) Hook up the TOYOTA hand±held tester to the DLC1 or DLC2.
(b) Clear the diagnostic trouble codes by following the prompts
on the tester screen.
HINT: Please refer to the TOYOTA hand±held tester opera-
tor 's manual for further details.
± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTINGRS±47

CONNECTORS
Slightly shake the connector vertically and horizontally.
Inspection of connectors
(a) Does the wire harness connecting with its corresponding
part have insufficient slack?
(b) Are the terminals dirty?
(c) Are the terminals making loose contact due to terminals
spread?
WIRE HARNESS
Slightly shake the wire harness vertically and horizontally.
Thoroughly check the connector joint, the fulcrum of the
vibration and the wiring opening in the engine/passenger
compartment panel.
PARTS AND SENSORS
Gently tap the part or sensor considered to be the problem
caused and check if the malfunction will occur.
CAUTION: Do not apply vibration to the center airbag
sensor assembly.
VIBRATION METHOD: When vibration seems to be the major cause.
SYMPTOM SIMULATION
ªIntermittent troubles or problemsº are the malfunctions about which the customer has a complaint, but which
do not occur and cannot be confirmed in the workshop. The intermittent problems also include complaints about
the SRS warning light going on and off erratically.
The self±diagnostic system stores the circuit of the intermittent problem in memory even if the ignition switch
is turned off.
For accurate diagnosis of the problems, ask the customer to obtain as much information as possible following
the customer problem analysis check sheet (See page RS±43) and try to reproduce the intermittent problem.
The problem simulation methods described below are the effective ways to reproduce the problem conditions
by applying vibration, heat, and humidity. RS±48
± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTING

DIAGNOSTIC TROUBLE CODE MATRIX CHART
If a malfunction code is displayed during the diagnostic trouble code check, check the circuit listed for that code
in the table below (Proceed to the page given for that circuit.).
 
 DTC No. 
 Diagnosis 
 Page
 (Normal)*1 
Source voltage drop RS±52
 
 
 
11
 
 
 

Short in squib circuit or front airbag sensor circuit (to ground)


Front airbag sensor or center airbag sensor assembly malfunction
 
 
 
RS±54
 
 
 
12 
 
 

Short in squib circuit (to B+)


Open in front airbag sensor circuits
 
 
 
RS±60
 13 
Short in D squib circuit (between D+ wire harness and D± wire harness) RS±66
 
 14
 
 
Open in D squib circuit
 
 RS±73
 
 15
 
 
Open in front airbag sensor circuit
 
 RS±78
 
 22*2 
 
SRS warning light system malfunction 
 RS±82
 31 
Center airbag sensor assembly malfunction RS±86
 
 53
 
 
Short in P squib circuit
 
 RS±87
 
 54
 
 
Open in P squib circuit
 
 RS±92
HINT:
*1 When the SRS warning light remains lit up and the diagnostic trouble code is the normal code, this means
a source voltage drop.
*
2 Code 22 is recorded when a malfunction occurs in the SRS warning light system.
If an open malfunction occurs in the SRS warning light system, the SRS warning light does not light up, so
that until the malfunction is repaired, the diagnostic trouble codes (including code 22) cannot be confirmed.
PROBLEM SYMPTOM CHART
Proceed with troubleshooting of each circuit in the table below.
RS±96
RS±98
Problem SymptomInspection ItemPage

Tc terminal circuit

SRS warning light system
Always lit up, when ignition
switch is in LOCK position.

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.

Diagnostic trouble code not displayed.

SRS warning light is always lit up with the DTC check procedure.

Diagnostic trouble code displayed without Tc and E1 terminal
correction.
RS±50± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTING

CENTER AIRBAG SENSOR ASSEMBLY CONNECTOR
 No. Symbol Terminal Name
 A ±± Electrical Connection Check Mechanism
 B ±± Electrical Connection Check Mechanism 
 1
 
 P± 
 Squib  (Front Passenger)
 2 P+ Squib
(Front Passenger)
 3 D+ Squib
(Driver)
 4 D± Squib  (Driver) 
 5
 
 E1
 
 Ground
 6 E2 Ground
 7 Tc Diagnosis
 8 +SL Front Airbag Sensor LH
 
 9
 
 ±SL
 
 Front Airbag Sensor LH 
 10 ±SR Front Airbag Sensor RH 
 11 +SR Front Airbag Sensor RH

 12 LA SRS Warning Light 
 13 
 IG2
 
 Power Source (IGN Fuse)
 14 ACC Power Source (CIG Fuse)
± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTINGRS±51

CIRCUIT INSPECTION
DTC (Normal) Source Voltage Drop
CIRCUIT DESCRIPTION
The SRS is equipped with a voltage±increase circuit (DC±DC converter) in the center airbag sensor assembly
in case the source voltage drops.
When the battery voltage drops, the voltage±increase circuit (DC±DC converter) functions to increase the volt-
age of the SRS to normal voltage.
The diagnostic system malfunction display for this circuit is different to other circuits±when the SRS warning light
remains lit up and the diagnostic trouble code is a normal code, voltage source drop is indicated.
Malfunction in this circuit is not recorded in the center airbag sensor assembly, and the voltage source returns
to normal, after approx. 10 seconds the SRS warning light automatically goes off.
 DTC No. Diagnosis 
 (Normal)
 
 Voltage source drop.
RS±52± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTING

INSPECTION PROCEDURES [P] Preparation [C] Check
(1) Turn ignition switch to LOCK.
(2) Disconnect center airbag sensor assembly con±
nector.
(3) Turn ignition switch ON. But do not start engine.
(4) Measure voltage at IG
2 or ACC on connector
wire harness side of center airbag sensor as±
sembly and operate electric system (defogger,
wiper, headlight, heater blower, etc.).
Voltage: 6 V Ð 11.5 V at IG
2 and ACC.
(5) Turn electric system switch OFF.
(6) Turn ignition switch to LOCK.
(7) Remove voltmeter and connect center sensor
assembly connector.
Preparation.
Does SRS warning light turn off?
Turn ignition switch ON.
Operate electric system checked in [1] (4) and
check that SRA warning light goes off.
Turn ignition switch ON.
Check battery and charging system.
(See charging system section)
Check diagnostic trouble code, and if a malfunc-
tion code is output, perform troubleshooting ac-
cording to malfunction code. If a normal code is
output, replace center airbag sensor assembly.
± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTINGRS±53

DTC 22 SRS Warning Light System Malfunction
CIRCUIT DESCRIPTION
The SRS warning light is located on the cluster finish panel.
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 E
1 of the DLC1 or DLC2 are connected, the diagnostic trouble code is displayed by the blinking
of the SRS warning light.
The SRS warning light circuit is equipped with an electrical connection check mechanism which detects when
the connector to the center airbag sensor assembly is not properly connected.
If the connector to the center airbag sensor assembly is not properly connected, the SRS warning light will not
light up.
Diagnostic trouble code 22 is recorded when a malfunction occurs in the SRS warning light system. If an OPEN
malfunction occurs in the SRS warning light system, the SRS warning light does not light up, so that until the
malfunction is repaired, the diagnostic trouble codes (including code 22) cannot be confirmed.
 
DTC No. 
Diagnosis 
 
 
22
 
 
 

Open circuit in SRS warning light system.


Center airbag sensor assembly malfunction.
RS±82± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTING

(See page RS±20).
(See page RS±10).
Check ECU±B Fuse.
Remove ECU±B fuse.
Check continuity of ECU±B fuse.
Continuity
Check connection of center airbag sensor assembly connector.
(1) Disconnect negative (±) terminal cable from the
battery, and wait at least 90 seconds.
(2) Remove steering wheel pad (See page RS±10).
(3) Disconnect connector of front passenger airbag
assembly (See page RS±20).
Preparation.
Repair.
Store the steering wheel pad with the front sur-
face facing upward.

Fuse may be burnt out even if it appears to be OK
during visual inspection.

If fuse is OK, install it.
INSPECTION PROCEDURES [P] Preparation [C] Check
HINT: If SRS warning light does not light up, perform the following troubleshooting:
± SUPPLEMENTAL RESTRAINT SYSTEMTROUBLESHOOTINGRS±83