Subaru Legacy IV (2008 year). Manual - part 1156

CC(diag)-6

Engine Control Module (ECM) I/O Signal

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

4. Engine Control Module (ECM) I/O Signal

A: ELECTRICAL SPECIFICATION

B: WIRING DIAGRAM

<Ref. to WI-194, WIRING DIAGRAM, Cruise Control System.>

Description

Terminal No.

Measurement condition and I/O signal

(Idling with ignition ON: except for cruise set light)

Main power 
supply

VB (CONTROL 1)
VB (CONTROL 2)

A7, B2

• Battery voltage is detected when the main power is turned ON.
• “0 V” is detected when the main power is turned OFF.

Command switch

B24

• “0 V” is detected when the command switch is in CANCEL position.
• “Approx. 1 V” is present when the command switch is in SET/COAST 
position.
• “Approx. 3 V” is detected when the command switch is in RESUME/
ACCEL position.
• “Approx. 4 V” is detected when the command switch is released.

Brake switch 1
(Brake switch)

B20

• Battery voltage is detected when the brake pedal is released.
• “0 V” is present when brake pedal is depressed.

Brake switch 2
(Stop light switch)

B28

• Battery voltage is present when brake pedal is depressed.
• “0 V” is detected when the brake pedal is released.

Main switch

B12

• “0 V” is present while the main switch is pressed or turned on.
• Approx. “5 V” is detected when the main switch is turned to OFF.

Ground

GND (CONTROL 1)
GND (CONTROL 2)

A5

D7

 — 

Ignition switch

B19

• Battery voltage is detected when the ignition switch is turned ON.
• “0 V” is detected when the ignition switch is turned OFF.

Clutch switch
(MT model)

C25

• “0 V” is present when brake pedal is depressed.
• Battery voltage is detected when the clutch pedal is released.

Neutral position switch (MT 
model)

C31

• Battery voltage is detected when the shift lever is in any position 
except for neutral.
• “Approx. 0 V” is detected when the shift lever is in neutral position.

Neutral signal (AT model)

C31

• Battery voltage is detected when the shift lever is in any position 
except for “P” or “N”.
• “0 V” is detected when the shift lever is in “P” or “N” position.

CC-00197

B134

9

30 29 28

32 31

20 19 18

22 21

10

12 11

14

24

34 33

27 26

17 16

1

2

3

4

5

6

7

13

23

15
25

8

B135

9

30 29 28

32

31

20

22 21

10

12 11

14

24

35

33

27 26

17 16

1

2

3

4

5

6

7

13

23

15
25

8

B136

9

30 29 28

32 31

20 19 18

22 21

10

12 11

14

24

34 33

27 26

16

1

2

3

4

5

6

13

23

15

25

8

B137

9

29 28

20 19 18

22 21

10

12 11

14

24

17 16

1

2

3

4

5

6

7

13

23

15

25

8

18

19

34

7

17

35

30

31

27 26

TO D:

TO C:

TO B:

TO A:

CC(diag)-7

Subaru Select Monitor

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

5. Subaru Select Monitor

A: OPERATION

1. GENERAL DESCRIPTION

The on-board diagnosis function of the cruise con-
trol system uses Subaru Select Monitor.
The on-board diagnosis function operates in two
categories, which are used depending on the type
of problems;
1) Cruise Control Cancel Conditions Diagnosis:

(1) This category of diagnosis requires actual
vehicle driving in order to determine the cause,
as when cruise speed is cancelled during driv-
ing although cruise cancel condition is not en-
tered.
(2) Cruise control memory in ECM stores the
cancel code which occurred during driving.
When there are multiple cancel code, they are
shown on the Subaru Select Monitor.

CAUTION:
• The cruise control memory stores not only
the cruise “cancel” which occurred (although
“cancel” operation is not entered by the driver),
but also the “cancel” condition input by the
driver.
• The content of the latest memory (the latest
code) is cleared when the ignition switch is
turned to OFF. However, memory contents set
by the diagnosis of faulty switches related to
the system and cruise control will remain as
trouble history (memory code) after the ignition
switch is turned to OFF.
2) Real-time Diagnosis:
Real-time diagnosis function is used to determine
whether or not the input signal system is in good or-
der, according to signal emitted from switches, sen-
sors, etc.

(1) Vehicle cannot be driven at cruise speed
when the problem occurs in the cruise control
system or relevant circuits.
(2) Monitor the signal conditions from switches
and sensors.

2. CRUISE CONTROL CANCEL 
CONDITIONS DIAGNOSIS

1) Prepare the Subaru Select Monitor kit.
2) Connect the diagnosis cable to Subaru Select
Monitor.
3) Connect the Subaru Select Monitor to data link
connector.

(1) Data link connector is located in the lower
portion of the instrument panel (on the driver’s
side).

(2) Connect the diagnosis cable to data link
connector.

4) Start the engine and turn the cruise control main
switch to ON.
5) Run the Subaru Select Monitor.
6) On the «Main Menu» display, select the {2. Each
System Check}.
On the «System Selection Menu» display, select
the {Engine Control System} and select the [OK].
Select the [OK] after the information of engine type
is displayed.
7) Drive vehicle at 40 km/h (25 MPH) or more and
set the cruise control.

CAUTION:
• When performing diagnosis, observe the le-
gal speed limit on the road.
• The cancel code will be also appear when
cruise control is cancelled by the driver’s oper-
ation. Do not confuse them.
• Be sure to get an assistant to support the di-
agnosis while driving, and have him/her oper-
ate the select monitor.

IM-00084

CC(diag)-8

Subaru Select Monitor

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

8) When the set speed is canceled by itself (when
cancelled without a cancel operation such as ap-
plying the brake) or if the cruise control could not be
set by performing the setting operation, selecting
the {Cancel Code(s) Display} on the engine mal-
function diagnosis screen will display the cancel
code on the select monitor display.

NOTE:
The {Latest Code} and {Memorized diagnostic
code(s)} are contained in the cancel code. The lat-
est code recognized during current test drive is dis-
played in {Latest Code}. Cancel codes resulting
from fault diagnosis of switches relating to the sys-
tem and cruise control are also displayed in {Mem-
orized diagnostic code(s)}.
9) Perform Engine DTC Clear Memory operation.
<Ref. to EN(H4SO)(diag)-50, OPERATION, Clear
Memory Mode.>
<Ref. to EN(H4DOTC)(diag)-52, OPERATION,
Clear Memory Mode.>
<Ref. to EN(H6DO)(diag)-52, OPERATION, Clear
Memory Mode.>
Cancel codes for switches relating to the system
and cruise control are deleted by clearing memory
on the engine side.

NOTE:
The latest code will be cleared by turning ignition
switch to OFF.

3. REAL-TIME DIAGNOSIS

1) Connect the Subaru Select Monitor.
2) Turn the ignition switch and cruise control main
switch to ON.
3) Run the Subaru Select Monitor.
4) On the «Main Menu» display, select the {2. Each
System Check}.
5) On the «System Selection Menu» display, select
the {Engine Control System}.
6) Select [OK] after engine type information is dis-
played.
7) Select {Current Data Display & Save} in Cruise
Control Diagnosis display screen.
8) Make sure that normal display is shown when
operated as follows:
• Depress and release the brake pedal. (Stop light
switch and brake switch are turned ON.)
• Turn the main switch to ON.
• Turn the “CANCEL” switch to ON.
• Turn the “SET/COAST” switch to ON.
• Turn the “RESUME/ACCEL” switch to ON.
• Depress or release the clutch pedal.
• Place the shift lever in any position other than
neutral.

NOTE:
• For detailed operation procedure, refer to the
“PC application help for Subaru Select Monitor”
• For detailed concerning cancel codes, refer to
the “List of Cancel Codes”. <Ref. to CC(diag)-11,
List of Cancel Code.>

CC(diag)-9

Diagnostics with Phenomenon

CRUISE CONTROL SYSTEM (DIAGNOSTICS)

6. Diagnostics with Phenomenon

A: DIAGNOSTIC PROCEDURE WITH PHENOMENON

Phenomenon

Check item

Reference

1

Cruise control main switch is 
not turned to ON. (Cruise 
indicator light does not illumi-
nate.)

(1) Perform cruise cancel 
conditions diagnosis.

Perform the diagnosis according to displayed cancel 
code.

(2) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(3) Check the cruise control 
command switch.

<Ref. to CC(diag)-13, 11, Diagnostic Procedure with 
Cancel Code.>

(4) Check the cruise indicator 
light.

<Ref. to CC(diag)-10, CHECK CRUISE INDICATOR 
LIGHT AND CRUISE SET INDICATOR LIGHT, Diagnos-
tics with Phenomenon.>

2

Cruise control cannot be set.

(1) Perform cruise cancel 
conditions diagnosis.

Perform the diagnosis according to displayed cancel 
code.

(2) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(3) Check the cruise control 
command switch.

<Ref. to CC(diag)-13, 11, Diagnostic Procedure with 
Cancel Code.>

(4) Check stop light switch 
and brake switch.

<Ref. to BR-39, Stop Light Switch.> <Ref. to CC(diag)-
15, 12, Diagnostic Procedure with Cancel Code.>

(5) Check clutch switch.

<Ref. to CL-37, Clutch Switch.> <Ref. to CC(diag)-17, 13, 
Diagnostic Procedure with Cancel Code.>

(6) Check the neutral posi-
tion switch.

<Ref. to CC(diag)-19, 14, Diagnostic Procedure with 
Cancel Code.> <Ref. to CC(diag)-26, 62, Diagnostic Pro-
cedure with Cancel Code.>

(7) Check vehicle speed sen-
sor.

<Ref. to CC(diag)-24, 22, Diagnostic Procedure with 
Cancel Code.>

3

Cruise set indicator light does 
not illuminate.

Check the cruise set indicator 
light.

<Ref. to CC(diag)-10, CHECK CRUISE INDICATOR 
LIGHT AND CRUISE SET INDICATOR LIGHT, Diagnos-
tics with Phenomenon.>

4

Vehicle speed is not held 
within set speed 

r3 km/h 

(

r2 MPH).

Check the vehicle speed sen-
sor.

<Ref. to CC(diag)-24, 22, Diagnostic Procedure with 
Cancel Code.>

5

Vehicle speed does not 
increase or does not return to 
set speed after RESUME/
ACCEL switch has been 
pressed.

(1) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(2) Check the RESUME/
ACCEL switch.

<Ref. to CC(diag)-13, 11, Diagnostic Procedure with 
Cancel Code.>

6

Vehicle speed does not 
decrease after SET/COAST 
switch has been pressed.

(1) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(2) Check the SET/COAST 
switch.

<Ref. to CC(diag)-13, 11, Diagnostic Procedure with 
Cancel Code.>

7

Cruise control is not released 
after CANCEL switch has 
been pressed.

(1) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(2) Check the CANCEL 
switch.

<Ref. to CC(diag)-13, 11, Diagnostic Procedure with 
Cancel Code.>

8

Cruise control is not released 
after brake pedal has been 
depressed.

(1) Perform the real-time 
diagnosis.

Check the input signal of cruise control system.

(2) Check stop light switch 
and brake switch.

<Ref. to CC(diag)-15, 12, Diagnostic Procedure with 
Cancel Code.> <Ref. to BR-39, INSTALLATION, Stop 
Light Switch.>