Subaru 2009 IMPREZA Service Manual page 2035

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
1 CHECK DTC.
2 CHECK BODY INTEGRATED UNIT.
1) Turn the ignition switch to "OFF".
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON.
4) Run the Subaru Select Monitor.
5) Read the data of "Stop Light Switch" using
Subaru Select Monitor. <Ref. to LAN(diag)-15,
OPERATION, Subaru Select Monitor.>
3 CHECK TCM.
Read the data of "Stop Light Switch" using Sub-
aru Select Monitor. <Ref. to 4AT(diag)-15,
OPERATION, Subaru Select Monitor.>
4 CHECK BODY INTEGRATED UNIT INPUT
SIGNAL.
1) Disconnect the harness connector of body
integrated unit.
2) Measure the voltage of harness between
body integrated unit and stop light switch.
Connector & terminal
(B280) No. 2 (+) — Chassis ground (–):
5 CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light
switch.
3) Measure the resistance of harness between
stop light switch connectors.
Connector & terminal
4 DOOR MODEL
(B65) No. 3 — No. 4:
5 DOOR MODEL
(B65) No. 1 — No. 2:
6 CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND STOP LIGHT
SWITCH.
1) Turn the ignition switch to ON.
2) Measure the voltage of harness between
the body integrated unit and chassis ground.
Connector & terminal
(B280) No. 2 (+) — Chassis ground (–):
7 CHECK POOR CONTACT.
Check
Is DTC of CAN communication
displayed?
Is "OFF" displayed?
Is "OFF" displayed?
Is the voltage 10 V or more?
Is the resistance 1 M or
more?
Is the voltage less than 1 V?
Is there poor contact of input
signal of brake switch?
4AT(diag)-50
Yes No
Perform the diag- Go to step 2.
nosis according to
DTC.
Go to step 3. Go to step 4.
Check for poor Replace the TCM.
contact in connec- <Ref. to 4AT-63,
tors or harnesses, Transmission Con-
and repair the trol Module
defective part. (TCM).>
Go to step 5. Go to step 7.
Go to step 6. Replace the stop
light switch.
Go to step 7. Repair the short
circuit of harness
between TCM and
stop light switch.
Repair the poor Check body inte-
contact. grated unit.