2004 SUBARU FORESTER Service Repair Manual

Page 1185 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-87
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK POWER SUPPLY TO REAR OXY-
GEN SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector fr

Page 1186 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-88
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
E: DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 2)
DTC DETECTING CONDITION:
Two consecutive driving

Page 1187 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-89
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector 
and chassis ground.

Page 1188 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-90
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
F: DTC P0068 MANIFOLD PRESSURE SENSOR RANGE/PERFORMANCE 
DTC DETECTING CONDITION:
Two consecutive driving cycles

Page 1189 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-91
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 DTC using 
“List of Dia

Page 1190 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-92
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
G: DTC P0107 MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE 
CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
Immediat

Page 1191 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-93
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake manifold absolute 
press

Page 1192 of 2870

SUBARU FORESTER 2004  Service Repair Manual EN(H4SO)-94
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to O