2004 SUBARU FORESTER Service Repair Manual

Page 1257 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-159
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC 
using “List o

Page 1258 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-160
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK CONDITION OF CAMSHAFT POSI-
TION SENSOR.
Turn the ignition switch to OFF.Is the camshaft position senso

Page 1259 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-161
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AM:DTC P0400 EXHAUST GAS RECIRCULATION FLOW
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault

Page 1260 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-162
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC 
using “List o

Page 1261 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-163
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK HARNESS BETWEEN EGR VALVE 
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Detach the connect

Page 1262 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-164
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AN:DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 
1)
DTC DETECTING CONDITION:
Two consecutive driv

Page 1263 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-165
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using

Page 1264 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-166
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AO:DTC P0458 EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CON-
TROL VALVE CIRCUIT LOW
DTC DETECTING CONDITION:
Two