Subaru IMPREZA GD 2007 Series Manual page 2703

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
P: DTC P0748 PRESSURE CONTROL SOLENOID "A" ELECTRICAL
DIAGNOSIS:
Output signal circuit of line pressure linear solenoid is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:
AT11
1 2
3 4
Step
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmission
and TCM.
3) Measure the resistance of harness between
TCM connector and transmission connector.
Connector & terminal
(B55) No. 3 — (B11) No. 2:
(B55) No. 4 — (B11) No. 1:
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND CHASSIS GROUND.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 3 — Chassis ground:
(B55) No. 4 — Chassis ground:
3 CHECK LINE PRESSURE LINEAR SOLE-
NOID.
Measure the resistance between transmission
connector receptacle's terminals.
Connector & terminal
(T4) No. 1 — No. 2:
B55
TCM
B11
T4
AT11
TRANSMISSION
B11
1 2
3 4
1 2
7 8 9
8
5 6 7
17 18 19 20
9 10 11 12
28 29 30
13 14 15
16
17 18 19
20
Is resistance less than 1 Ω?
Is the resistance 1 MΩ or
more?
Is the resistance 4 — 8 Ω?
4AT(D)(diag)-64
LINE
PRESSURE
LINEAR
SOLENOID
B55
3 4 5 6
10 11 12 13 14 15 16
21 22 23 24 25 26 27
31 32 33 34 35
Check Yes
Go to step 2.
Go to step 3.
Repair the poor
contact.
AT-03522
No
Repair the open
circuit of harness
between TCM and
transmission con-
nector.
Repair the short
circuit of harness
between TCM and
transmission con-
nector.
Go to step 4.