Subaru Impreza 2003 Service Manual page 1707

DIAGNOSTIC PROCEDURE FOR POWER INDICATOR LIGHT
Step
1 CHECK BATTERY TERMINAL.
Turn the ignition switch to OFF.
2 CHECK POWER SUPPLY OF TCM.
1)Disconnect the connector from TCM.
2)Turn the ignition switch to ON.
3)Measure the voltage between TCM connec-
tor and chassis ground.
Connector & terminal
(B56) No. 1 (+) — Chassis ground ( − − − − ):
3 CHECK FUSE (NO. 4).
Remove the fuse (No. 4).
4 CHECK IGNITION POWER SUPPLY CIR-
CUIT.
1)Turn the ignition switch to ON (engine OFF).
2)Measure the ignition power supply voltage
between TCM connector and chassis ground.
Connector & terminal
(B54) No. 23 (+) — Chassis ground (–):
(B54) No. 24 (+) — Chassis ground (–):
5 CHECK FUSE (NO. 11).
Remove the fuse (No. 11).
6 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from TCM and
transmission.
3)Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B56) No. 19 — (B11) No. 16:
(B54) No. 21 — (B11) No. 16:
7 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND TRANSMISSION
GROUND.
Measure the resistance of harness between
transmission and transmission ground.
Connector & terminal
(T4) No. 16 — Transmission ground:
8 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in control
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Check
Is there poor contact at battery
terminal?
Is the voltage 10 — 13 V?
Is the fuse (No. 4) blown out?
Is the voltage 10 — 13 V?
Is the fuse (No. 11) blown out? Replace the fuse
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
module power supply, ground
line and data link connector?
4AT-37
Yes
Repair or tighten Go to step 2.
the battery termi-
nal.
Go to step 4. Go to step 3.
Replace the fuse Repair the open
(No. 4). If replaced circuit in harness
fuse (No. 4) has between fuse (No.
blown out easily, 4) and TCM, or
repair short circuit fuse (No. 4) and
in harness battery, and poor
between fuse (No. contact in cou-
4) and TCM. pling connector.
Go to step 6. Go to step 5.
Repair the open
(No. 11). If circuit in harness
replaced fuse (No. between fuse (No.
11) has blown out 4) and TCM, or
easily, repair short fuse (No. 4) and
circuit in harness battery, and poor
between fuse (No. contact in cou-
11) and TCM. pling connector.
Go to step 7. Repair the open
circuit in harness
between TCM,
transmission har-
ness connector,
and poor contact
in coupling con-
nector.
Go to step 8. Repair the open
circuit in harness
between transmis-
sion and transmis-
sion ground.
Repair the con- Replace the TCM.
nector. <Ref. to 4AT-70,
Transmission Con-
trol Module
(TCM).>
No