Subaru Legacy III (2000-2003 year). Manual — part 596

AT-118

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

8

CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and transmis-

sion.

2) Lift-up or raise the vehicle and place safety

stands.

NOTE:

Raise all wheels off floor.

3) Start the engine and set vehicle in 20 km/h

(12 MPH) condition.

NOTE:

The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-22, Clear Memory
Mode.> or <Ref. to VDC-25, Clear Memory
Mode.>

4) Measure voltage between TCM connector

terminals.

Connector & terminal

(B55) No. 24 (+) — (B54) No. 19 (

−−−−

):

Does the measured value exceed the spec-
ified value?

AC 1 V

Even if “POWER”
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
harness or con-
nector in the TCM
and transmission.

Go to step 11.

9

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect connectors to TCM and transmis-

sion.

2) Connect Subaru Select Monitor to data link

connector.

3) Lift-up or raise the vehicle and place safety

stands.

NOTE:

Raise all wheels off floor.

4) Turn ignition switch to ON and turn Subaru

Select Monitor switch to ON.

5) Start the engine.
6) Read data of vehicle speed using Subaru

Select Monitor.

•Compare speedometer with Subaru Select
Monitor indications.
•Vehicle speed is indicated in “km/h” or “MPH”.
7) Slowly increase vehicle speed to 60 km/h

or 37 MPH.

NOTE:

The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-22, Clear Memory
Mode.> or <Ref. to VDC-25, Clear Memory
Mode.>

Does the speedometer indication increase
as the Subaru Select Monitor data
increases?

Speedometer indication
increases as the Subaru Select
Monitor data increases

Even if “POWER”
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
harness or con-
nector in the TCM
and transmission.

Go to step 11.

Step

Value

Yes

No

AT-119

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

10

CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Connect connectors to TCM and transmis-

sion.

2) Lift-up or raise the vehicle and place safety

stands.

NOTE:

Raise all wheels off floor.

3) Set oscilloscope to TCM connector termi-

nals.

Connector & terminal

Positive probe; (B55) No. 24
Ground; (B54) No. 19

4) Start the engine and set vehicle in 20 km/h

(12 MPH) condition.

NOTE:

The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-22, Clear Memory
Mode.> or <Ref. to VDC-25, Clear Memory
Mode.>

5) Measure signal voltage indicated on oscillo-

scope.
Does signal voltage exceed the the speci-
fied value?

AC 1 V

Even if “POWER”
indicator lights up,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
harness or con-
nector in the TCM
and transmission.

Go to step 11.

11

CHECK POOR CONTACT.
Is there poor contact in rear vehicle speed sen-
sor circuit?

There is poor contact.

Repair poor con-
tact.

Replace TCM.
<Ref. to AT-76,
Transmission Con-
trol Module
(TCM).>

Step

Value

Yes

No

AT-120

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

AT-121

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR NO-DIAGNOSTIC TROUBLE CODE (DTC)

15.Diagnostic Procedure for No-diagnostic Trouble Code (DTC)

A: CHECK GEAR POSITION.

Step

Value

Yes

No

1

CHECK GEAR POSITION.
1) Lift-up the vehicle and place safety stand.

NOTE:

Raise all wheels off ground.

2) Start the engine.
3) Move select lever to “D”, and drive vehicle.
4) Read data of gear position using Subaru

Select Monitor.

•Gear position is indicated.

NOTE:

The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control di-
agnosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system. <Ref. to ABS-22, Clear Memory
Mode.> or <Ref. to VDC-25, Clear Memory
Mode.>

Does the transmission gear
correspond to the gear which
is shown on display?

Go to step 2.

Check shift sole-
noid 1 and shift
solenoid 2 signal
circuit. <Ref. to
AT-72, DTC 71
SHIFT SOLE-
NOID 1, Diagnos-
tic Procedure with
Diagnostic Trou-
ble Code (DTC).>
and <Ref. to AT-
76, DTC 72 SHIFT
SOLENOID 2,
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC).>

2

CHECK SPECIFICATIONS.
Is vehicle with VDC system or SPORT shift?

With VDC system or SPORT
shift

Go to step CHECK
BRAKE SWITCH.
<Ref. to AT-125,
CHECK BRAKE
SWITCH., Diag-
nostic Procedure
for No-diagnostic
Trouble Code
(DTC).>

Go to step CHECK
FWD SWITCH.
<Ref. to AT-122,
CHECK FWD
SWITCH., Diag-
nostic Procedure
for No-diagnostic
Trouble Code
(DTC).>