Subaru IMPREZA GD 2007 Series Manual page 1488

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 27 (+) — Chassis ground (–):
2 CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
wastegate control solenoid valve.
3) Measure the resistance between wastegate
control solenoid valve connector and engine
ground.
Connector & terminal
(B127) No. 1 — Engine ground:
3 CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID
VALVE.
Measure the resistance of harness between
ECM and wastegate control solenoid valve con-
nector.
Connector & terminal
(B137) No. 27 — (B127) No. 1:
4 CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Remove the wastegate control solenoid
valve.
2) Measure the resistance between wastegate
control solenoid valve terminals.
Terminals
No. 1 — No. 2:
5 CHECK POWER SUPPLY TO WASTEGATE
CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between wastegate
control solenoid valve and engine ground.
Connector & terminal
(B127) No. 2 (+) — Engine ground (–):
Check
Is the voltage 10 V or more?
Is the resistance 1 MΩ or more? Go to step 3.
Is the resistance less than 1 Ω? Go to step 4.
Is the resistance between 10 —
100 Ω?
Is the voltage 10 V or more?
EN(STI)(diag)-157
ENGINE (DIAGNOSTICS)
Yes No
Repair poor con- Go to step 2.
tact of the ECM
connector.
Repair ground
short circuit of har-
ness between
ECM and waste-
gate control sole-
noid valve
connector.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and waste-
gate control sole-
noid valve
connector
• Poor contact of
coupling connector
Go to step 5. Replace the waste-
gate control sole-
noid valve. <Ref. to
FU(H4DOTC)-45,
Wastegate Control
Solenoid Valve.>
Repair poor con- Repair the harness
tact in wastegate and connector.
control solenoid
NOTE:
valve connector.
In this case, repair
the following item:
• Open circuit of
harness between
main relay and
wastegate control
solenoid valve
connector
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor