Subaru 2009 IMPREZA Service Manual page 594

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 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. 28 — Chassis ground:
2 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. 4 — Engine ground:
Check
Is the resistance 1 M or
more?
Is the resistance 1 M or
more?
EN(H4SO)(diag)-177
ENGINE (DIAGNOSTICS)
Yes No
Go to step 2. Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Replace the elec- Repair the short
tronic throttle con- circuit to ground in
trol. <Ref. to harness between
FU(H4SO)-14, ECM and elec-
Throttle Body.> tronic throttle con-
trol connector.
Replace the ECM if
defective. <Ref. to
FU(H4SO)-45,
Engine Control
Module (ECM).>