1991 LEXUS SC400 Service Repair Manual

Page 3609 of 4087

LEXUS SC400 1991  Service Repair Manual 
YESNO
NOYES
YES
NO
OKNG
BASIC INSPECTION
When the normal code is displayed in the diagnostic code check, troubleshoot\
ing should be performed in the
order for all possible circuits to be considered

Page 3610 of 4087

LEXUS SC400 1991  Service Repair Manual 
OKNG
OKNG
5Check idle speed.
C
OK
P(1) Warm up engine at normal operating temperature.
(2) Switched off all accessories.
(3) Switched off air conditioner.
(4) Shift transmission into ªNº range.
(5)

Page 3611 of 4087

LEXUS SC400 1991  Service Repair Manual 
OKNG
OKNG
7Check fuel pressure.
C
P(1) Be sure that fuel is enough in tank.
(2) Turn ignition switch on.
(3) Using SST, connect terminals FP and + B of checkconnector.
SST 09843±18020
Check that pul

Page 3612 of 4087

LEXUS SC400 1991  Service Repair Manual 
FAIL±SAFE CHART
If any of the following codes is recorded, the ECU enters fail±safe mod\
e.
Code No.Fail±Safe OperationFail±Safe Deactivation Conditions
14Fuel cut1 IGF detected in consecutive 3

Page 3613 of 4087

LEXUS SC400 1991  Service Repair Manual 
PARTS LOCATION
±
ENGINE TROUBLESHOOTING Parts locationTR±27 
WhereEverybodyKnowsYourName

Page 3614 of 4087

LEXUS SC400 1991  Service Repair Manual 
WIRING DIAGRAM
TR±28±
ENGINE TROUBLESHOOTING Wiring Diagram 
WhereEverybodyKnowsYourName

Page 3615 of 4087

LEXUS SC400 1991  Service Repair Manual 
±
ENGINE TROUBLESHOOTING Wiring DiagramTR±29 
WhereEverybodyKnowsYourName

Page 3616 of 4087

LEXUS SC400 1991  Service Repair Manual 
TERMINALS OF ECU
Connectors  of the engine & ECT ECU are water±proof and are the
bolt type.
For water proof type connectors, in order to measure the voltage
of ECU terminals and the resistance of co