Subaru 2009 IMPREZA Service Manual page 690

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
22 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control relay connector and chassis
ground.
Connector & terminal
(B220) No. 32 — Chassis ground:
(B220) No. 30 — Chassis ground:
23 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
Measure the resistance between ECM and
electronic throttle control relay connector.
Connector & terminal
(B136) No. 21 — (B220) No. 32:
(B136) No. 1 — (B220) No. 30:
24 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
electronic throttle control.
3) Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B134) No. 19 — Chassis ground:
(B134) No. 18 — Chassis ground:
(B134) No. 18 — (B136) No. 6:
(B134) No. 28 — Chassis ground:
25 CHECK SHORT CIRCUIT INSIDE THE ECM.
1) Connect the connector to ECM.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 6 — Engine ground:
(E57) No. 4 — Engine ground:
26 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness between
ECM and electronic throttle control connector.
Connector & terminal
(B134) No. 18 — (E57) No. 6:
(B134) No. 28 — (E57) No. 4:
(B134) No. 29 — (E57) No. 3:
Check
Is the resistance 1 M or
more?
Is the resistance less than 1 ? Go to step 24.
Is the resistance 1 M or
more?
Is the resistance 1 M or
more?
Is the resistance less than 1 ? Go to step 27.
EN(H4SO)(diag)-273
ENGINE (DIAGNOSTICS)
Yes No
Go to step 23. Repair the short
circuit in harness
to ground between
ECM and elec-
tronic throttle con-
trol relay
connector.
Repair the open
circuit in harness
between ECM and
electronic throttle
control relay con-
nector.
Go to step 25. Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Go to step 26. Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Replace the ECM if
defective. <Ref. to
FU(H4SO)-45,
Engine Control
Module (ECM).>
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