Subaru Legacy III (2000-2003 year). Manual — part 1002

CC-28

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

DIAGNOSTICS CHART WITH TROUBLE CODE

B: DTC 22 VEHICLE SPEED SENSOR

DIAGNOSIS:
Disconnection or short circuit of vehicle speed sensor system.
TROUBLE SYMPTOM:
Cruise control cannot be set. (Cancelled immediately.)
WIRING DIAGRAM:

CRUISE

CONTROL

MODULE

B17

B94

GE

3

1

2

BATTERY

M/B NO. 5

C17

AT

19

6

B94

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

IGNITION

RELAY

VEHICLE SPEED

SENSOR (MT)

B56

C:

TRANSMISSION

CONTROL

MODULE

MT

B17

1 2 3

B56

C:

CC-00099

16

B22

E3

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

1 2

7

8

9

5 6

3 4

10 11 12
19 20 21

13

14 15

16

17

18

22

23

24

CC-29

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

DIAGNOSTICS CHART WITH TROUBLE CODE

Step

Value

Yes

No

1

CHECK TRANSMISSION TYPE.
Is the transmission type MT?

Transmission type is MT.

Go to step 2.

Go to step 6.

2

CHECK HARNESS BETWEEN BATTERY
AND VEHICLE SPEED SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect harness connector from vehicle

speed sensor.

3) Turn ignition switch to ON.
4) Measure voltage between vehicle speed

sensor harness connector terminal and
chassis ground.

Connector & terminal

(B17) No. 3 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 3.

Check harness for
open or short
between ignition
relay and vehicle
speed sensor.

3

CHECK HARNESS BETWEEN CRUISE CON-
TROL MODULE AND VEHICLE SPEED SEN-
SOR.
1) Turn ignition switch to OFF.
2) Disconnect harness connector from cruise

control module.

3) Measure resistance between vehicle speed

sensor harness connector terminal and
cruise control module harness connector
terminal.

Connector & terminal

(B17) No. 1 — (B94) No. 19:

Is the measured value less than the speci-
fied value?

10

Ω

Go to step 4.

Repair harness.

4

CHECK HARNESS BETWEEN VEHICLE
SPEED SENSOR AND ENGINE GROUND.
Measure resistance between vehicle speed
sensor harness connector terminal and engine
ground.

Connector & terminal

(B17) No. 2 (+) — Engine ground (

−−−−

):

Is the measured value less than the specified
value?

10

Ω

Go to step 5.

Repair harness.

5

CHECK VEHICLE SPEED SENSOR.
1) Connect harness connector to vehicle

speed sensor.

2) Lift-up the vehicle and support with safety

stands.

3) Drive the vehicle at speed greater than 20

km/h (12 MPH).

Warning:

Be careful not to be caught up by the run-
ning wheels.

4) Measure voltage between cruise control

module harness connector terminal and
chassis ground.

Connector & terminal

(B94) No. 19 (+) — Chassis ground (

−−−−

):

Is the measured value same as the speci-
fied value?

0

←→

5 V

Replace cruise
control module.
<Ref. to CC-6,
Cruise Control
Module.>

Replace vehicle
speed sensor.

CC-30

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

DIAGNOSTICS CHART WITH TROUBLE CODE

6

CHECK HARNESS BETWEEN CRUISE CON-
TROL MODULE AND TRANSMISSION CON-
TROL MODULE.
1) Turn ignition switch to OFF.
2) Disconnect harness connector from trans-

mission control module and cruise control
module.

3) Measure resistance between cruise control

module harness connector terminal and
transmission control module harness con-
nector terminal.

Connector & terminal

(B94) No. 19 — (B56) No. 17:

Is the measured value less than the speci-
fied value?

10

Ω

?

Go to step 7.

Repair harness.

7

CHECK TRANSMISSION CONTROL MOD-
ULE.
1) Connect harness connector to transmission

control module.

2) Lift-up the vehicle and support with safety

stands.

3) Drive the vehicle faster than 10 km/h (6

MPH).

Warning:

Be careful not to be caught by the running
wheels.

4) Measure voltage between transmission

control module harness connector terminal
and chassis ground.

Connector & terminal

(B56) No. 17 (+) — Chassis ground (

−−−−

):

Is the measured value same as the speci-
fied value?

0

←→

5 V

Replace cruise
control module.
<Ref. to CC-6,
Cruise Control
Module.>

Replace transmis-
sion control mod-
ule. <Ref. to AT-
76, Transmission
Control Module
(TCM).>

Step

Value

Yes

No

CC-31

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

DIAGNOSTICS CHART WITH TROUBLE CODE

C: DTC 28 WIRING HARNESS OPENED.

Step

Value

Yes

No

1

CHECK BATTERY.
Measure battery specific gravity of electrolyte.
Does the measured value exceed the specified
value?

1.250

Go to step 2.

Charge or replace
battery. Go to step
2.

2

CHECK FUSES, CONNECTORS AND HAR-
NESSES.
Check the condition of the main and other
fuses, and harnesses and connectors. Also
check for proper grounding.
Is there anything unusual about the appear-
ance of main fuse, fuse, harness, connector
and grounding?

Fuse, harness, connector and
grounding are OK.

End of inspection. Repair or replace

faulty parts.