Subaru 2009 IMPREZA Service Manual page 1393

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
wastegate control solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 27 (+) — Chassis ground (–):
2 CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between wastegate
control solenoid valve terminals.
Terminals
No. 1 — No. 2:
AS:DTC P0301 CYLINDER 1 MISFIRE DETECTED
NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-173, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
AT:DTC P0302 CYLINDER 2 MISFIRE DETECTED
NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-173, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
AU:DTC P0303 CYLINDER 3 MISFIRE DETECTED
NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-173, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
Check
Is the voltage 10 V or more?
Is the resistance less than 1 ? Replace the waste-
EN(H4DOTC)(diag)-172
Yes No
Repair short cir- Go to step 2.
cuit to power in the
harness between
ECM and waste-
gate control sole-
noid valve
connector.
Repair the poor
gate control sole- contact of ECM
noid valve. <Ref. to connector.
FU(H4DOTC)-47,
Wastegate Control
Solenoid Valve.>