Subaru 2009 IMPREZA Service Manual page 502

Diagnostic Procedure for Subaru Select Monitor Communication
Step
1 CHECK POWER SUPPLY CIRCUIT.
Connect the SDI (Subaru Diagnosis Interface)
or general scan tool to data link connector.
2 CHECK POWER SUPPLY CIRCUIT.
Measure the voltage between data link connec-
tor and chassis ground.
Connector & terminal
(B40) No. 16 (+) — Chassis ground (–):
3 CHECK HARNESS BETWEEN DATA LINK
CONNECTOR AND CHASSIS GROUND.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between
data link connector and chassis ground.
Connector & terminal
(B40) No. 4 — Chassis ground:
(B40) No. 5 — Chassis ground:
4 CHECK HARNESS BETWEEN ECM AND
DATA LINK CONNECTOR.
1) Disconnect the connectors from ECM,
TCM, ABS CM, VDC CM, airbag CM and body
integrated unit.
CAUTION:
When disconnecting the connector from air-
bag control module, always follow the pre-
cautions on AB section. <Ref. to AB-5,
CAUTION, General Description.>
2) Measure the resistance of harness between
ECM and data link connector.
Connector & terminal
(B136) No. 16 — (B40) No. 7:
5 CHECK HARNESS BETWEEN ECM AND
DATA LINK CONNECTOR.
Measure the resistance between data link con-
nector and chassis ground.
Connector & terminal
(B40) No. 7 — Chassis ground:
Check
Does SDI or general scan tool
turn ON?
Is the voltage 10 V or more?
Is the resistance less than 5 ? Repair the poor
Is the resistance less than 1 ? Go to step 5.
Is the resistance 1 M or
more?
EN(H4SO)(diag)-85
ENGINE (DIAGNOSTICS)
Yes No
Go to step 4. Go to step 2.
Go to step 3. Repair the power
supply circuit.
NOTE:
In this case, repair
the following item:
• Open or ground
short circuit of har-
ness between bat-
tery and data link
connector
• Blown out of fuse
(M/B No. 13)
Repair the harness
contact of data link and connector.
connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and data link
connector
• Open circuit of
harness between
ECM and engine
ground
• Poor contact of
ECM connector
• Poor contact of
joint connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and data link
connector
• Poor contact of
joint connector
Repair the poor Repair the ground
contact of the ECM short circuit of har-
or data link con- ness between
nector. ECM and data link
connector.