1991 LEXUS SC400 Service Repair Manual

Page 2657 of 4087

LEXUS SC400 1991  Service Repair Manual 
Location of Connectors in Body
TR±46±
ENGINE TROUBLESHOOTING Locations of Connectors 
WhereEverybodyKnowsYourName

Page 2658 of 4087

LEXUS SC400 1991  Service Repair Manual 
±MEMO ±
±
ENGINE TROUBLESHOOTINGTR±47 
WhereEverybodyKnowsYourName

Page 2659 of 4087

LEXUS SC400 1991  Service Repair Manual 
CIRCUIT INSPECTIONDiag. Code  12
RPM Signal Circuit (No.1)
CIRCUIT DESCRIPTION
Cam position sensors (G1 and G2 signals) and engine speed sensor (NE sig\
nal) consist of a signal plate
and a pick up c

Page 2660 of 4087

LEXUS SC400 1991  Service Repair Manual 
DIAGNOSTIC CHART
WIRING DIAGRAM
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±49 
WhereEverybodyKnowsYourName

Page 2661 of 4087

LEXUS SC400 1991  Service Repair Manual 
OKNG
INSPECTION PROCEDURE
1Check engine speed sensor, No. 1, No. 2 cam position sensor
C
OK
PFor engine speed sensor.
(2) Remove engine under cover.
(2) Disconnected engine speed sensor connector.
Fo

Page 2662 of 4087

LEXUS SC400 1991  Service Repair Manual 
OKNG
OKNG
2Check for open and short in harness and connector between engine & ECT ECU an\
d each sen-
sor (See page IN±27).
Repair or replace harness or connector.
3Inspect sensor installation and t

Page 2663 of 4087

LEXUS SC400 1991  Service Repair Manual 
Diag. Code 13RPM Signal Circuit (No.2)
CIRCUIT DESCRIPTION
Refer to RPM signal circuit (No. 1) on page TR±48.
Code No.Diagnostic Code Detecting ConditionTrouble Area
No NE signal to ECU for 0.1 sec.

Page 2664 of 4087

LEXUS SC400 1991  Service Repair Manual 
MEMO ±
ENGINE TROUBLESHOOTINGTR±53 
WhereEverybodyKnowsYourName