Infiniti M45 (Y34). Manual — part 8

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-25

[ASCD]

C

D

E

F

G

H

I

J

L

M

A

B

ACS

ASCD PUMP CIRCUIT CHECK

1.

CHECK ASCD PUMP

1.

Disconnect ASCD pump connector.

2.

Measure resistance between ASCD pump terminals 1 and 2, 3, 4.

Refer to wiring diagram in

ACS-11, "FIG. 4"

.

OK or NG

OK

>> GO TO 2.

NG

>> Replace ASCD pump.

2.

CHECK ASCD PUMP CIRCUIT

1.

Disconnect ASCD control unit connector.

2.

Check harness for open or short between ASCD control unit terminals and ASCD pump terminals.

OK or NG

OK

>> GO TO 3.

NG

>> Repair harness or connector.

Terminals

Resistance [

Ω

]

1

2

Approx. 65

3

Approx. 65

4

Approx. 3

PBIC0214E

Terminal (Wire color)

ASCD control unit

ASCD pump

Connector

M35

E16

ASCD pump power supply

12 (R/PU)

1 (LG)

Air valve

13 (L/R)

2 (L/R)

Release valve

1 (L/Y)

3 (L/Y)

Vacuum motor

14 (W/R)

4 (W/R)

Continuity should exist.

PBIC0215E

ACS-26

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

3.

CHECK ASCD PUMP POWER SUPPLY

With CONSULT-II

1.

Jack up the drive wheels.

2.

Start the engine.

3.

See “PW SUP-VALVE” in “DATA MONITOR” mode.

4.

Maintain the conditions below.

–

Vehicle speed is more than 40 km/h (25 MPH).

–

Main switch (CRUISE lamp) is ON.

–

Set/coast switch (SET lamp) is ON.

Without CONSULT-II

1.

Jack-up the drive wheels.

2.

Start the engine.

3.

Maintain the conditions below.

–

Vehicle speed is more than 40 km/h (25 MPH).

–

Main switch (CRUISE lamp) is ON.

–

Set/coast switch (SET lamp) is ON.

Check voltage between ASCD control unit harness connector M35
terminal 12 (R/PU) and ground.

OK or NG

OK

>> ASCD pump power supply is OK.

NG

>> Replace ASCD control unit.

“PW SUP–VALVE” should be ON.

PKIA2377E

Battery voltage should exist.

PBIC0217E

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-27

[ASCD]

C

D

E

F

G

H

I

J

L

M

A

B

ACS

ASCD ACTUATOR/PUMP CHECK

1.

CHECK VACUUM HOSE

Check vacuum hose (between ASCD actuator and ASCD pump) for
breakage, cracks or fracture.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace vacuum hose.

2.

CHECK ASCD WIRE

Check wire for improper installation, rust formation or breaks.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace wire. Refer to

ACS-30, "ASCD Wire Adjustment"

.

3.

CHECK ASCD ACTUATOR

1.

Disconnect vacuum hose from ASCD actuator.

2.

Connect the hose of hand vacuum pump to ASCD actuator.

OK or NG

OK

>> GO TO 4.

NG

>> Replace ASCD actuator.

MEL402G

Apply —40 kPa (—0.41 kg/cm

2

, —5.8 psi) vacuum to

ASCD actuator with hand vacuum pump.

ASCD wire should move to pull throttle drum.

Wait 10 seconds and check for decrease in vacuum
pressure.

Vacuum pressure
decrease:

Less than 2.7 kPa (0.028

kg/cm

2

, 0.39 psi)

PBIC0218E

ACS-28

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

4.

CHECK ASCD PUMP

1.

Disconnect vacuum hose from ASCD pump and ASCD pump connector.

2.

If necessary remove ASCD pump.

3.

Connect vacuum gauge to ASCD pump.

4.

Apply 12V direct current to ASCD pump and check operation.

OK or NG

OK

>> INSPECTION END.

NG

>> Replace ASCD pump.

ECM SIGNAL CHECK

1.

CHECK THROTTLE POSITION SENSOR SIGNAL CIRCUIT

1.

Disconnect ASCD control unit connector and ECM connector.

2.

Check continuity between ASCD control unit harness connector
M35 terminal 3 (R/G) and ECM harness connector F102 termi-
nal 113 (R/Y).

Refer to wiring diagram in

ACS-11, "FIG. 4"

OK or NG

OK

>> GO TO 2.

NG

>> Repair harness or connector.

12V direct current supply ter-
minals

Operation

(+)

(—)

Air valve

1

2

Close

Release valve

3

Close

Vacuum motor

4

Operate

A vacuum pressure of at least —40 kPa (—0.41 kg/cm

2

,

—5.8 psi) should be generated.

PBIC0219E

Continuity should exist.

PBIC0220E