Nissan Xterra. Manual - part 340

EC-486

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

VIAS

OK or NG

OK

>> Repair or replace power valve actuator.

NG

>> GO TO 4.

4.

CHECK VACUUM HOSE

1. Stop engine.

2. Check hoses and tubes between intake manifold and power

valve actuator for cracks, clogging, improper connection or dis-

connection. Refer to 

EC-41, "Vacuum Hose Drawing"

.

OK or NG

OK

>> GO TO 5.

NG

>> Repair hoses or tubes.

5.

CHECK VACUUM TANK

Refer to 

EC-487, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace vacuum tank. Refer to 

EM-25, "Exploded View"

.

6.

CHECK VIAS CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect VIAS control solenoid valve harness connector.

3. Turn ignition switch ON.

4. Check voltage between terminal 1 and ground with CONSULT

or tester.

OK or NG

OK

>> GO TO 8.

NG

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E2, F32

• Harness for open or short between VIAS control solenoid valve and ECM

>> Repair harness or connectors.

8.

CHECK VIAS CONTROL SOLENOID VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check harness continuity between ECM terminal 39 and VIAS control solenoid valve terminal 2.

Refer to Wiring Diagram.

Condition

Vacuum

12V direct current supply

Should exist.

No supply

Should not exist.

SEF109L

1

: Power valve actuator

2

: VIAS control solenoid valve

: Front

Voltage: Battery voltage

AWBIA0684ZZ

VIAS

EC-487

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

4. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 9.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

9.

CHECK VIAS CONTROL SOLENOID VALVE

Refer to 

EC-487, "Component Inspection"

.

OK or NG

OK

>> GO TO 10.

NG

>> Replace VIAS control solenoid valve. Refer to 

EM-25, "Exploded View"

.

10.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009484236

VIAS CONTROL SOLENOID VALVE

 With CONSULT

1. Reconnect harness connectors disconnected.
2. Turn ignition switch ON.
3. Perform “VIAS S/V-1” in “ACTIVE TEST” mode.
4. Check air passage continuity and operation delay time under the

following conditions.

Operation takes less than 1 second.

 Without CONSULT

Check air passage continuity and operation delay time under the fol-

lowing conditions.

Operation takes less than 1 second.

VACUUM TANK

Continuity should exist.

Condition

VIAS SOL VALVE

Air passage continuity 

between (A) and (B)

Air passage continuity 

between (A) and (C)

ON

Yes

No

OFF

No

Yes

JMBIA0180ZZ

Condition

Air passage continuity 

between (A) and (B)

Air passage continuity 

between (A) and (C)

12V direct current supply 
between terminals 1 and 2

Yes

No

No supply

No

Yes

PBIB2532E

EC-488

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

VIAS

1. Disconnect vacuum hose connected to vacuum tank.

2. Connect a vacuum pump to the port (A) of vacuum tank.

3. Apply vacuum and make sure that vacuum exists at the port (B).

PBIB0846E

ENGINE CONTROL SYSTEM SYMPTOMS

EC-489

< SYMPTOM DIAGNOSIS >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

SYMPTOM DIAGNOSIS

ENGINE CONTROL SYSTEM SYMPTOMS

Symptom Matrix Chart

INFOID:0000000009484237

SYSTEM — BASIC ENGINE CONTROL SYSTEM

SYMPTOM

Reference 
page

HARD/NO ST

AR

T

/REST

AR

T

 (EXCP

. 

H

A

)

ENGINE ST

ALL

HESIT

A

TION/SURGING/FLA

T

 SPOT

SP

ARK KNOCK/DET

O

NA

TION

LACK

 OF POWER/

POOR 

ACC

E

LERA

TION

HIGH IDL

E/LOW

 IDLE

ROUG

H IDLE/HUNTING

IDLI

NG VIBRA

TION

SLOW

/NO RETURN T

O

 IDLE

OVERHEA

T

S/W

A

TER TEMPERA

T

UR

E

 HIGH

EXCESS

IVE F

U

E

L CONSUMP

T

IO

N

EXCESS

IVE OIL CONSUMP

T

ION

BA

TTER

Y

 DEAD (UNDER CHARGE)

Warranty symptom code

AA

AB

AC

AD

AE

AF AG AH

AJ

AK

AL

AM HA

Fuel

Fuel  pump  circuit

1

1

2

3

2

2

2

3

2

EC-467

Fuel  pressure  regulator  system

3

3

4

4

4

4

4

4

4

4

EC-494

Fuel  injector  circuit

1

1

2

3

2

2

2

2

EC-463

Evaporative  emission  system

3

3

4

4

4

4

4

4

4

4

EC-32

Air

Positive crankcase ventilation sys-
tem

3

3

4

4

4

4

4

4

4

4

1

EC-480

Incorrect idle speed adjustment

1

1

1

1

1

EC-118

Electric  throttle  control  actuator

1

1

2

3

3

2

2

2

2

2

2

EC-429

, 

EC-435

Ignition Incorrect  ignition  timing  adjustment

3

3

1

1

1

1

1

1

EC-118

Ignition  circuit

1

1

2

2

2

2

2

2

EC-470

Power  supply  and  ground  circuit

2

2

3

3

3

3

3

2

3

EC-149

Mass air flow sensor circuit

1

1

2

2

2

2

2

2

EC-168

, 

EC-172

Engine coolant temperature sensor circuit

3

3

3

EC-185

, 

EC-192

Air fuel ratio (A/F) sensor 1

EC-200
EC-204
EC-207
EC-229
EC-420

Throttle position sensor circuit

2

2

EC-188

, 

EC-261

, 

EC-379

, 

EC-381

, 

EC-444

Accelerator pedal position sensor circuit

3

2

1

EC-149

, 

EC-437

, 

EC-440

, 

EC-448