Subaru 2009 IMPREZA Service Manual page 2062

Diagnostic Procedure without Diagnostic Trouble Code (DTC)
Step
5 CHECK INDICATOR.
1) Turn the ignition switch to OFF.
2) Install a fuse to the FWD fuse holder.
3) Start the engine and wait for 2 seconds or
more.
6 CHECK BODY INTEGRATED UNIT.
7 CHECK TCM.
1) Turn the ignition switch to OFF.
2) Install a fuse to the FWD fuse holder.
3) Connect the Subaru Select Monitor to data
link connector.
4) Turn the ignition switch to ON.
5) Read the data of "FWD Switch" using Sub-
aru Select Monitor.
8 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FUSE BOX.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
fuse box.
3) Measure the resistance of the harness
between TCM and fuse box.
Connector & terminal
(B54) No. 10 — (B158) No. 7:
9 CHECK HARNESS CONNECTOR BETWEEN
FUSE BOX AND CHASSIS GROUND.
Measure the resistance of the harness between
fuse box and chassis ground.
Connector & terminal
(i5) No. 13 — Chassis ground:
10 CHECK POOR CONTACT.
Check poor contact of FWD switch circuit.
11 CHECK TCM.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine.
4) Read the data of "Engine Speed" using Sub-
aru Select Monitor.
12 CHECK TCM.
Read the data of "FWD Switch" using Subaru
Select Monitor.
13 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FUSE BOX.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
fuse box.
3) Measure the resistance of harness connec-
tor between TCM and chassis ground.
Connector & terminal
(B54) No. 10 — Chassis ground:
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Check
Is the AWD warning light illumi-
nated?
Is DTC of CAN communication
displayed?
Is "ON" displayed?
Is the resistance less than 1 ? Go to step 9.
Is the resistance less than 1 ? Go to step 10.
Is there poor contact of FWD
switch circuit?
Is the measured value 400 rpm
or more?
Is "OFF" displayed?
Is the resistance 1 M or
more?
4AT(diag)-77
Yes No
Normal. Finish the Go to step 6.
diagnosis.
Perform the diag- Go to step 7.
nosis according to
DTC.
Perform the self- Go to step 8.
diagnosis of com-
bination meter.
Repair the open
circuit of harness
between TCM and
fuse box.
Repair the open
circuit of harness
between fuse box
and chassis
ground.
Repair the poor Replace the TCM.
contact. <Ref. to 4AT-63,
Transmission Con-
trol Module
(TCM).>
Go to step 12. Inspect the ECM.
Perform the self- Go to step 13.
diagnosis of com-
bination meter.
Replace the TCM. Repair the short
<Ref. to 4AT-63, circuit of harness
Transmission Con- between TCM and
trol Module fuse box.
(TCM).>