Infiniti F50. Manual - part 8

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-25

[ASCD]

C

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3. 

CHECK ASCD PUMP POWER SUPPLY

With CONSULT-II

1.

Jack up the drive wheels.

2.

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

3.

Maintain the conditions below.

–

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

–

MAIN (CRUISE) switch (CRUISE lamp) is ON.

–

SET/COAST switch (SET lamp) is ON.

Without CONSULT-II

1.

Jack-up the drive wheels.

2.

Maintain the conditions below.

–

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

–

MAIN (CRUISE) switch (CRUISE lamp) is ON.

–

SET/COAST switch (SET lamp) is ON.

Check voltage between ASCD control unit harness connector M35
terminal 12 (R/L) 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

ACS-26

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

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-29, "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

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

ACS-27

[ASCD]

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4. 

CHECK ASCD PUMP

1.

Disconnect vacuum hose from ASCD pump and ASCD pump harness 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 ECM harness connector and ASCD control unit harness connector.

2.

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

OK or NG

OK

>> GO TO 2.

NG

>> Repair harness or connector.

2. 

CHECK ECM COMMUNICATION CIRCUIT

1.

Check continuity between ECM harness connector F101 termi-
nal 39 (OR) and ASCD control unit harness connector M35 ter-
minal 7 (OR).

2.

Check continuity between ASCD control unit harness connector
M35 terminal 7 (OR) and ground.

OK or NG

OK

>> GO TO 3.

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

7 – 39

: Continuity should exist

7 – ground

: Continuity should not exist.

SKIA3062E

ACS-28

[ASCD]

AUTOMATIC SPEED CONTROL DEVICE (ASCD)

3. 

CHECK ECM

1.

Check ECM.
Refer to 

EC-407, "DTC P0605 ECM"

 .

OK or NG

OK

>> Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

NG

>> Replace ECM.

TCS MONITOR CHECK

1. 

CHECK TCS MONITOR CIRCUIT

1.

Turn ignition key switch OFF.

2.

Remove instrument lower driver panel.

3.

Remove ASCD control unit connectors and TCS control unit
connectors.

4.

Check continuity between ASCD control unit harness connector
M35 terminal 2 (SB) and TCS control unit harness connector
E218 terminal 14 (SB).

OK or NG

OK

>> GO TO 2.

NG

>> Repair harness or connector.

2. 

CHECK TCS CONTROL UNIT

●

Check TCS Control unit. Refer to 

BRC-42, "Inspection 3 VDC/TCS/ABS Control Unit System"

 .

OK or NG

OK

>> TCS control unit is OK.

NG

>> Replace TCS control unit.

2 – 14

: Continuity should exist

2 – ground

: Continuity should not exist.

PKIA2626E