Page 913 of 1807
I02711
LOCK
Disconnect
HORN (+)
DI-622
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
850 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check voltage between terminal HORN of theft deterrent and door lock ECU con-
nector and body ground.
PREPARATION:
(a) Remove the instrument panel. (See page BO-50).
(b) Disconnect the ECU connector.
CHECK:
Measure voltage between terminal HORN of theft deterrent
ECU connector and body ground.
OK:
Voltage : 10 - 14 V
OK Check and replace theft deterrent and door lock
ECU.
NG
Check and repair harness and connector between theft deterrent and door lock ECU and horn
relay (See page IN-28).
Page 914 of 1807
N09783
2
2AEA1II1
IB6 IF219 622
7
1
2
1
BatteryR/B No.2
HAZ-HORNW
(2JZ-GE)Theft Deterrent and
Door Lock ECU T13
(2JZ-GE)
11
(2JZ-GTE)
Theft Deterrent
Horn (2JZ-GTE)
BP-B W
WW-LW-L
SHa
b P-B
W-L
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
DI-623
851 Author: Date:
1997 SUPRA (RM502U)
Theft Deterrent Horn Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, contact ºaº and contact ºbº in the ECU close alternately in cycles
of approximately 0.2 sec., causing the theft deterrent horn to blow (See the wiring diagram below).
In this condition, if any of the following operations is done, the contact ºaº in the ECU opens, thus stopping
the theft deterrent horn from blowing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to the ACC or ON position.
(3) Approximately 1 minute elapses.
WIRING DIAGRAM
DI4X4-01
Page 915 of 1807
I02542
LOCK
Disconnect
2JZ-GE
2JZ-GTE2 (+)
2 (+)
N14682
1 (+)
2 (-)
DI-624
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
852 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check voltage between terminal SH of theft deterrent horn connector and body
ground.
PREPARATION:
Remove the theft deterrent horn and disconnect the connector.
CHECK:
Measure voltage between terminal 1 of theft deterrent horn
connector and body ground.
OK:
Voltage : 10 - 14 V
NG Check and repair harness and connector be-
tween HORN fuse and theft deterrent horn.
OK
2 Check theft deterrent horn.
CHECK:
Connect positive lead to terminal 1 and negative lead to
terminal 2 of theft deterrent horn connector.
OK:
Theft deterrent horn blows.
NG Replace theft deterrent horn.
OK
Page 916 of 1807
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
DI-625
853 Author: Date:
1997 SUPRA (RM502U)
3 Check harness and connector between theft deterrent and door lock ECU and
theft deterrent horn (See page IN-28).
NG Check and repair harness or connector.
OK
Check and replace theft deterrent ECU.
Page 917 of 1807

I02543
Theft Deterrent and
Door Lock ECU
*1: USA Models
*2: CANADA Models BatteryR/B No.2
HEAD
(LH)*1
HEAD
(LH-L WR)*2HEAD R/B No.2
FL MAIN
Light Control
Switch
R/B No.2
HEAD
(RH)*1
HEAD
(RH-L WR)*2R-Y R-Y R-Y R-Y
R-G R-B
W-B
W-B BRR 2
2
2
22
22
2
11 1 1
4
23
10 16 13
IB2
IF2 2A
EA Headlight Relay
T13
DI-626
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
854 Author: Date:
1997 SUPRA (RM502U)
Headlight Control Relay Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, it causes the Tr in the ECU to switch on and off at approximately
0.2 sec. intervals. This switches the headlight control relay on and off, thus flashing the headlights (See the
wiring diagram below).
In this condition, if any of the following operations is done, the Tr in the ECU goes off and the headlight control
relay switches off, thus stopping the headlights flashing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to the ACC or ON position.
(3) Approximately 1 minute elapses.
WIRING DIAGRAM
DI4X5-01
Page 918 of 1807
I02544
LOCK
Disconnect
HEAD (+)
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
DI-627
855 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
HINT:
The flow chart below is based on the premise that the headlights light up normally whenever the light control
switch is operated. If headlight operation is not normal when the light control switch is operated, proceed
to troubleshooting on page BE-2.
1 Check voltage between terminal HEAD of theft deterrent and door lock ECU con-
nector and body ground.
PREPARATION:
(a) Remove the instrument panel. (See page BO-50)
(b) Disconnect the ECU connector.
CHECK:
Measure voltage between terminal HEAD of theft deterrent
ECU connector and body ground.
OK:
Voltage: 10 - 14 V
OK Check and replace theft deterrent and door lock
ECU.
NG
Check and repair harness and connector between theft deterrent and door lock ECU and head-
light control relay (See page IN-28).
Page 919 of 1807

I02545
I02545
Theft Deterrent and
Door Lock ECUT13
IF2
2 2
2A22 J/B No.1
1B 1K
1C
LG LGG-W G-W
G-WTAIL 11
16
3 5TAIL 1 W-L
W-B
Ta i l
Light
W-B
W-B
1
193
B
Battery
Light
Failure
Sensor
Light Control Switch15
23
G
Taillight Control Relay
B1
BJ
ALT
POWER
W
1
5
5 2 DI-628
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
856 Author: Date:
1997 SUPRA (RM502U)
Taillight Control Relay Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, it causes the Tr in the ECU to switch on and off at approximately
0.2 sec. intervals. This switches the taillight control relay on and off, thus the taillights flash (See the wiring
diagram below).
In this condition, if any of the following operations is done, the Tr in the ECU goes off and the taillight control
relay switches off, thus stopping the taillights flashing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to the ACC or ON position.
(3) Approximately 1 minute elapses.
WIRING DIAGRAM
DI4X6-01
Page 920 of 1807
I02546
LOCK
Disconnect
TAIL (+)
- DIAGNOSTICSTHEFT DETERRENT SYSTEM
DI-629
857 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check voltage between terminal TAIL of theft deterrent door lock ECU connector
and body ground.
PREPARATION:
(a) Remove the instrument panel. (See page BO-50)
(b) Disconnect the ECU connector.
CHECK:
Measure voltage between terminal TAIL of theft deterrent and
door lock ECU connector and body ground.
OK:
Voltage: 10 - 14 V
OK Check and replace theft deterrent ECU.
NG
Check and repair harness and connector between theft deterrent and door lock ECU and taillight
control relay (See page IN-28).