Infiniti F50. Manual — part 6

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-17

[ASCD]

C

D

E

F

G

H

I

J

L

M

A

B

ACS

Trouble Diagnoses

EKS003OF

SYMPTOM CHART

*1: It indicates that system is in fail-safe. After completing diagnostic procedures, perform “FAIL-SAFE SYSTEM CHECK” (

ACS-18

) to

verify repairs.
*2: If vehicle speed is greater than 40 km/h (25 MPH) after system has been released, pressing RESUME/ACCEL switch returns vehicle
speed to the set speed previously achieved. However, doing so when the MAIN (CRUISE) switch is turned to “OFF”, vehicle speed will
not return to the set speed since the memory is canceled.
*3: Check only MAIN (CRUISE) switch built-in steering switch.

PROCEDURE

Diagnostic procedure

REFERENCE PAGE (ACS-

)

ACS-

18

ACS-19

ACS-

20

ACS-

22

ACS-

23

ACS-

24

ACS-

26

ACS-

27

ACS-

28

SYMPTOM

F

A

IL-

SAFE SYSTEM

CH

E

C

K

POW

E

R

SUPP

L

Y

AND GROUND

CIRCUI

T CHECK

ASCD BRAKE/ST

O

P

LAM

P

SW

IT

CH CHECK

ASCD

STEERING SW

IT

CH CHECK

VEHICLE SPEED SENSOR

CHECK

ASCD PUMP

CIRCUI

T CHECK

ASCD ACTUA

T

O

R

/PUMP CH

E

C

K

ECM

SI

GNAL CHECK

TCS MONI

T

O

R

CHECK

ASCD cannot be set. (“CRUISE” indicator
lamp does not ON.)

X

X*3

ASCD cannot be set. (“SET” indicator lamp
does not blink.)

X

X

X

X

ASCD cannot be set. (“SET” indicator lamp
blinks.*1)

X

X

X

X

X

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

X

X

Vehicle speed does not return to the set
speed after RESUME/ACCEL switch has
been pressed.*2

X

X

Vehicle speed does not increase after
RESUME/ACCEL switch has been pressed.

X

X

X

System is not released after CANCEL switch
(steering) has been pressed.

X

X

Large difference between set speed and
actual vehicle speed.

X

X

X

X

Deceleration is greatest immediately after
ASCD has been set.

X

X

X

X

ACS-18

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

FAIL-SAFE SYSTEM CHECK

1.

Turn ignition switch to ON position.

2.

Turn MAIN (CRUISE) switch to ON and check if the “set indica-
tor” blinks.
If the indicator lamp blinks, check the following.

●

ASCD steering switch. Refer to

ACS-22, "ASCD STEERING

SWITCH CHECK"

.

3.

Drive the vehicle at more than 40 km/h (25 MPH) and push SET/
COAST switch.
If the indicator lamp blinks, check the following.

●

Vehicle speed sensor. Refer to

ACS-23, "VEHICLE SPEED

SENSOR CHECK"

.

●

ASCD pump circuit. Refer to

ACS-24, "ASCD PUMP CIR-

CUIT CHECK"

.

●

If vehicle speed sensor and ASCD pump circuit are OK,
replace ASCD control unit.

4.

Depress brake pedal slowly (brake pedal should be depressed
more than 5 seconds).
If the indicator lamp blinks, check the following.

●

ASCD brake/stop lamp switch. Refer to

ACS-20, "ASCD

BRAKE/STOP LAMP SWITCH CHECK"

.

5.

END. (System is OK.)

SEL417V

SEL767P

SAT797A

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-19

[ASCD]

C

D

E

F

G

H

I

J

L

M

A

B

ACS

POWER SUPPLY AND GROUND CIRCUIT CHECK

1.

CHECK POWER SUPPLY CIRCUIT FOR ASCD CONTROL UNIT

1.

Disconnect ASCD control unit harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between ASCD control unit harness connector
M35 terminal 5 (W/G) and ground.

Refer to wiring diagram in

ACS-8, "FIG. 1"

.

Yes or No

Yes

>> GO TO 2.

No

>> Check the following.

●

10A fuse [No. 12 located in the fuse block (J/B) NO.1]

●

Harness for open or short

2.

CHECK GROUND CIRCUIT FOR ASCD CONTROL UNIT

Check continuity between ASCD control unit harness connector M35
terminal 4 (B/W), 17(B) and ground.

Refer to wiring diagram in

ACS-8, "FIG. 1"

.

Yes or No

Yes

>> Power supply and ground circuit is OK.

No

>> Repair harness or connector.

Dose battery voltage exist?

PBIC0203E

Dose continuity exist?

SKIA3060E

ACS-20

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ASCD BRAKE/STOP LAMP SWITCH CHECK

1.

CHECK ASCD BRAKE SWITCH CIRCUIT

With CONSULT-II

See “BRAKE SW” in “DATA MONITOR” mode.

Without CONSULT-II

1.

Disconnect ASCD control unit harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between ASCD control unit harness connector
M35 terminal 8 (GY/R) and ground.

OK or NG

OK

>> GO TO 2.

NG

>> Check the following.

●

ASCD brake switch
Refer to

ACS-29, "Electrical Component Inspection"

.

●

Park/neutral position switch
Refer to

AT-235, "PARK/NEUTRAL POSITION, MANUAL MODE, BRAKE AND THROTTLE

POSITION SWITCH CIRCUIT"

.

●

Park/neutral position relay
Refer to

ACS-29, "Electrical Component Inspection"

.

●

Harness for open or short

when brake pedal is depressed or A/T
selector lever is in “N” or “P” range:

BRAKE SW OFF

When brake pedal is released and A/T
selector lever is not in “N” or “P”
range:

BRAKE SW ON

PBIC0205E

When brake pedal is depressed or A/T
selector lever is in “N” or “P” range:

Approx. 0 V

When brake pedal is released and A/T
selector lever is not in “N” or “P”
range:

Battery voltage
should exist.

PBIC0206E