Subaru Legacy 2004 Service Manual page 2290

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK IGNITION POWER SUPPLY CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear vehicle
speed sensor.
Turn the ignition switch to ON.
3) Measure the ignition power supply voltage
between rear vehicle speed sensor connector
and transmission ground.
Connector & terminal
(AT1) No. 3 (+) — Transmission ground (
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between TCM and rear vehicle speed sensor
connector.
Connector & terminal
(B54) No. 23 — (AT1) No. 1:
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and rear vehicle speed sensor connector.
Connector & terminal
(B54) No. 24 — (AT1) No. 2:
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 23 — Chassis ground:
5 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B54) No. 24 — Chassis ground:
6 PREPARE OSCILLOSCOPE.
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Check
Is the voltage more than 10 V? Go to step 2.
$
):
Is the resistance less than 1
"?
Is the resistance less than 1
"?
Is the resistance more than 1
M"?
Is the resistance more than 1
M"?
Do you have an oscilloscope? Go to step 8.
4AT(diag)-87
Yes
Check the harness
between rear vehi-
cle speed sensor
and battery for
open circuit, short
or poor contact.
Repair the har-
ness if required.
Go to step 3. Repair the open
circuit or poor con-
tact of connector in
harness between
TCM and rear
vehicle speed sen-
sor connector.
Go to step 4. Repair the open
circuit or poor con-
tact of connector in
harness between
TCM and rear
vehicle speed sen-
sor connector.
Go to step 5. Repair the short
circuit in harness
between TCM and
rear vehicle speed
sensor connector.
Go to step 6. Repair the short
circuit in harness
between TCM and
rear vehicle speed
sensor connector.
Go to step 7.
No