Page 841 of 1807
F03405
Throttle Control ECU
IND
T162
W
IF21
W
C127 SLIP
Indicator
Light
C10 Y
1E12 J/B No.1
GAUGE9
DI-550
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
778 Author: Date:
1997 SUPRA (RM502U)
SLIP Indicator Light Circuit
CIRCUIT DESCRIPTION
The SLIP indicator blinks during TRAC operation.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check SLIP indicator light.
See combination meter troubleshooting on page BE-2.
NG Repair or replace combination meter.
OK
2 Check for short in harness and connector between throttle control ECU and SLIP
indicator light (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace throttle control ECU.
DI4WA-01
Page 842 of 1807

F03406F03406
Throttle Control ECU SNOW
Indicator
Light J/B No.1
SNOW Mode Switch
(TRAC Control Switch)SIND
SNOW GAUGEP-G
P-G
R-B W-B
W-B
W-B
YT1611
T1614 IF19
C125
C109
1E12
IE IG8 6
F03407
6
8
SNOW Mode Switch
(TRAC Control Switch)
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-551
779 Author: Date:
1997 SUPRA (RM502U)
SNOW Indicator Light, SNOW Mode Switch Circuit
CIRCUIT DESCRIPTION
When you push the SNOW mode switch, TRAC control becomes SNOW mode operation and the SNOW
indicator light on, and when you push the TRAC OFF switch, TRAC control will be released to normal mode
operation and the SNOW indicator light goes off.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check SNOW mode switch.
PREPARATION:
(a) Remove SNOW mode switch (TRAC control switch).
(b) Disconnect TRAC control switch connector.
CHECK:
Measure resistance between terminals 6 and 8 of TRAC control
switch when SNOW mode switch on and off.
OK:
TRAC control switchResistance
SNOW mode switch pushed inContinuity
TRAC OFF switch pushed in1 MW or higher
NG Replace TRAC control switch.
OK
DI4WB-01
Page 843 of 1807
DI-552
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
780 Author: Date:
1997 SUPRA (RM502U)
2 Check for open and short in harness and connector between SNSW of throttle
control ECU and TRAC control switch and body ground (See page IN-28).
NG Repair or replace harness or connector.
OK
3 Check SNOW indicator light.
See combination meter troubleshooting on page BE-2.
NG Repair or replace combination meter.
OK
4 Check for short in harness and connector between throttle control ECU and
SNOW indicator light (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace throttle control ECU.
Page 844 of 1807
F03408
Throttle Control ECU
12V
Tc
R R
R P-B DLC1
Tc E1 BR
BR
BR
BRDLC2
E1Tc
3 11
21
11 3
18
ED3
4
IJ1II1
IF1
T16 P-B
S-17-1F02201F03525
DLC2DLC1
E
1
TcE1
Tc
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-553
781 Author: Date:
1997 SUPRA (RM502U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
By connecting terminals Tc and E1 of DLC1 or DLC2, the ECU displays the DTC by blinking the TRAC OFF
indicator light.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals Tc and E1 of DLC2 or DLC1.
PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminals Tc and E1 of DLC2 or
DLC1.
OK:
Voltage: 10 - 14 V
OK Proceed to next circuit inspection shown on
problem symptoms chart (See page DI-508).
NG
DI4WC-01
Page 845 of 1807
DI-554
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
782 Author: Date:
1997 SUPRA (RM502U)
2 Check for open and short in harness and connector between throttle control
ECU and DLC2 or DLC1, DLC2 or DLC1 and body ground (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace throttle control ECU.
Page 846 of 1807
DI4WD-01
Vehicle Brought to Workshop
Customer Problem Analysis
Warning Light Check
DTC Check
DTC Chart
DI-560
Circuit Inspection
Remains on
Normal and Malfunction Code
Symptom Simulation
DTC Check
Identification of Problem
Warning Light Check
Confirmation Test
Warning Light ON
Warning Light Remains Off
END
Normal
Normal
1
2
3
4
7
Repair
85
6
Step
,:Diagnostic steps permitting the use
of the TOYOTA hand-held tester.3
6
DI-556
DI-557IN-18
DI-564 to DI-603 DI-557
DI-557
DI-557
Remains ON
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-555
783 Author: Date:
1997 SUPRA (RM502U)
SUPPLEMENTAL RESTRAINT SYSTEM
HOW TO PROCEED WITH TROUBLESHOOTING
Perform troubleshooting in accordance with the procedure on the following pages.
Page 847 of 1807
DI4WE-01
Supplemental Restraint System Check Sheet
Date Problem Occurred
Customer 's Name
Registration No.
Registration Year
Frame No.
Odometer Reading
Weather
Temperature
Vehicle Operation
Road Conditions
Details Of Problem
Vehicle Inspection, Repair Histo-
ry
Prior to Occurrence of Mal-
function(Including Supplemental
Restraint System)
Diagnosis System Inspection
SRS Warning Light
Inspection
DTC Inspection1st Time
2nd Time
1st Time
2nd TimeInspector 's
Name
Fine Cloudy Rainy Snowy Other
Approx.
Starting Idling
Driving [ Constant speed Acceleration Deceleration
Other ]
Remains ON Sometimes Light Up Does Not Light Up
Remains ON Sometimes Light Up
Does Not Light Up
Normal Code Malfunction Code
Normal Code Malfunction Code[ Code. ]
[ Code. ]km
Miles //
//
// Date Vehicle Brought In
DI-556
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
784 Author: Date:
1997 SUPRA (RM502U)
CUSTOMER PROBLEM ANALYSIS CHECK
Page 848 of 1807

DI4WF-01
R06853
H03184
E1Tc
TcE
1
DLC 1
DLC 2
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-557
785 Author: Date:
1997 SUPRA (RM502U)
PRE-CHECK
1. CHECK SRS WARING LIGHT
(a) Turn the ignition switch to ACC or ON and check that the
SRS warning light lights up.
(b) Check that the SRS warning light goes out after approx.
6 seconds.
HINT:
When the ignition switch is at ACC or ON and the SRS
warning light remains on or flashes, the airbag sensor as-
sembly has detected a malfunction code.
If, after approx. 6 seconds have elapsed, the SRS warn-
ing light sometimes lights up or the SRS warning light
lights up even when the ignition switch is OFF, a short in
the SRS warning light circuit can be considered likely.
Proceed to ºSRS warning light system malfunctionº on
page DI-598, DI-600.
2. CHECK DTC (Using diagnosis check wire)
(a) Using diagnosis check wire, check the output of DTC.
(1) Turn the ignition switch to ACC or ON position and
wait approx. 20 seconds.
(2) Using SST, connect the terminals Tc and E
1 of the
DLC1.
HINT:
DTC check and troubleshooting of each DTC can also be done
using DLC2.
SST 09843-18020
NOTICE:
Never make a mistake with the terminal connection posi-
tion as this will cause a malfunction.