Subaru 2009 IMPREZA Service Manual page 1506

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
33 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
electronic throttle control.
3) Measure the resistance between ECM and
electronic throttle control connector.
Connector & terminal
(B137) No. 5 — (E57) No. 2:
(B137) No. 4 — (E57) No. 1:
34 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 2 (+) — Engine ground (–):
(E57) No. 1 (+) — Engine ground (–):
35 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 2 — Engine ground:
(E57) No. 1 — Engine ground:
36 CHECK ELECTRONIC THROTTLE CON-
TROL MOTOR HARNESS.
Measure the resistance between electronic
throttle control connectors.
Connector & terminal
(E57) No. 2 — (E57) No. 1:
37 CHECK ELECTRONIC THROTTLE CON-
TROL GROUND CIRCUIT.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:
38 CHECK ELECTRONIC THROTTLE CON-
TROL.
Measure the resistance between electronic
throttle control terminals.
Terminals
No. 1 — No. 2:
39 CHECK ELECTRONIC THROTTLE CONTROL.
Move the throttle valve to the fully open and fully
closed positions with fingers.
Check that the valve returns to the specified
position when releasing fingers.
Check
Is the resistance less than 1 ? Go to step 34.
Is the voltage 5 V or more?
Is the resistance 1 M or
more?
Is the resistance 1 M or
more?
Is the resistance less than 5 ? Go to step 38.
Is the resistance 50
Does the valve return to the
specified position? Standard
value: 3 mm (0.12 in) from fully
closed position
EN(H4DOTC)(diag)-285
ENGINE (DIAGNOSTICS)
Yes
Repair the short
circuit to power in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Go to step 36.
Go to step 37.
or less? Go to step 39.
Repair the poor
contact of ECM
connector.
No
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and electron-
ic throttle control
connector
• Poor contact of
coupling connector
Go to step 35.
Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Repair the short
circuit of harness
between ECM and
electronic throttle
control connector.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and engine
ground
• Poor contact of
coupling connector
Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(H4DOTC)-14,
Throttle Body.>
Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(H4DOTC)-14,
Throttle Body.>