Subaru 2009 IMPREZA Service Manual page 3399

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
LAN SYSTEM (DIAGNOSTICS)
Step
6 CHECK DTC.
1) Turn the ignition switch to OFF.
2) Connect the disconnected connectors.
3) Start the engine.
4) Read the DTC of body integrated unit using
Subaru Select Monitor.
7 CHECK DTC.
Read all DTCs using the Subaru Select Monitor.
8 CHECK HARNESS.
1) Turn the ignition switch to OFF.
2) Shake the harness used for CAN communi-
cation circuit.
3) Turn the ignition switch to ON.
4) Read the DTC of body integrated unit using
Subaru Select Monitor.
9 CHECK CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect all the connector that is con-
nected to high speed CAN circuit.
Check
Is U1221 a current malfunc-
tion?
Are DTCs P1718 or P0044,
P0045, P0140 detected?
Is U1221 a current malfunc-
tion?
Is there poor contact of connec-
tor terminal?
LAN(diag)-66
Yes No
Go to step 7. Go to step 8.
Replace the ECM. Replace the body
<Ref. to integrated unit.
FU(H4SO)-45, <Ref. to SL-50,
REMOVAL, Engine REMOVAL, Body
Control Module Integrated Unit.>
(ECM).> <Ref. to
FU(H4DOTC)-52,
REMOVAL, Engine
Control Module
(ECM).>
Repair or replace Go to step 9.
the harness.
Repair the connec- Temporary poor
tor terminal where contact occurs.
poor contact
exists, or replace
harness.