Infiniti QX56 (JA60). Manual - part 456

EC-476

< ECU DIAGNOSIS >

[VK56DE]

ECM

1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once. Wait at least 10

seconds and then turn it ON (engine stopped) again.

2. Perform 

TM-30, "OBD-II Diagnostic Trouble Code (DTC)"

. (The DTC in TCM will be erased)

3. Select Service $04 with GST (Generic Scan Tool).

 No Tools

NOTE:

If the DTC is not for AT related items (see 

EC-459, "DTC Index"

), skip step 2.

1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once.

Wait at least 10 seconds and then turn it ON (engine stopped) again.

2. Perform 

TM-30, "OBD-II Diagnostic Trouble Code (DTC)"

. (The DTC in the TCM will be erased.)

3. Change the diagnostic test mode from Mode II to Mode I by depressing the accelerator pedal. Refer to

EC-55, "Malfunction Indicator Lamp (MIL)"

.

• If the battery is disconnected, the emission-related diagnostic information will be lost within 24

hours.

• The following data are cleared when the ECM memory is erased.

- Diagnostic trouble codes

- 1st trip diagnostic trouble codes

- Freeze frame data

- 1st trip freeze frame data

- System readiness test (SRT) codes

- Test values

Actual work procedures are explained using a DTC as an example. Be careful so that not only the DTC, but all

of the data listed above, are cleared from the ECM memory during work procedures.

ENGINE CONTROL SYSTEM SYMPTOMS

EC-477

< SYMPTOM DIAGNOSIS >

[VK56DE]

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:0000000005149500

SYSTEM — BASIC ENGINE CONTROL SYSTEM

SYMPTOM

Refer-
ence 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-399

Fuel  pressure  regulator  system

3

3

4

4

4

4

4

4

4

4

EC-489

Injector  circuit

1

1

2

3

2

2

2

2

EC-396

Evaporative  emission  system

3

3

4

4

4

4

4

4

4

4

EC-37

Air

Positive crankcase ventilation sys-
tem

3

3

4

4

4

4

4

4

4

4

1

EC-417

Incorrect idle speed adjustment

1

1

1

1

1

EC-13

Electric  throttle  control  actuator

1

1

2

3

3

2

2

2

2

2

2

EC-356

, 

EC-359

 , 

EC-363

 , 

EC-365

Ignition

Incorrect  ignition  timing  adjustment

3

3

1

1

1

1

1

1

EC-13

Ignition  circuit

1

1

2

2

2

2

2

2

EC-407

Main  power  supply  and  ground  circuit

2

2

3

3

3

3

3

2

3

EC-82

EC-478

< SYMPTOM DIAGNOSIS >

[VK56DE]

ENGINE CONTROL SYSTEM SYMPTOMS

1 - 6: The numbers refer to the order of inspection.
(continued on next page)

SYSTEM — ENGINE MECHANICAL & OTHER

Mass air flow sensor circuit

1

1

2

2

2

2

2

2

EC-104

, 

EC-110

Engine coolant temperature sensor circuit

3

3

3

EC-121

, 

EC-129

Air fuel ratio (A/F) sensor 1 circuit

EC-137

, 

EC-141

 , 

EC-145

 , 

EC-149

 , 

EC-382

  

Throttle position sensor circuit

2

2

EC-125

, 

EC-188

 , 

EC-306

 , 

EC-308

 , 

EC-374

Accelerator pedal position sensor circuit

3

2

1

EC-284

, 

EC-367

 , 

EC-370

 , 

EC-378

Knock sensor circuit

2

3

EC-198

Crankshaft position sensor (POS) circuit

2

2

EC-201

Camshaft position sensor (PHASE) circuit

3

2

EC-205

Vehicle speed signal circuit

2

3

3

3

EC-275

Power steering pressure sensor circuit

2

3

3

EC-281

ECM

2

2

3

3

3

3

3

3

3

3

3

EC-284

, 

EC-286

Intake valve timing control solenoid valve cir-
cuit

3

2

1

3

2

2

3

3

EC-101

Park/Neutral position (PNP) signal circuit

3

3

3

3

3

EC-292

Refrigerant pressure sensor circuit

2

3

3

4

EC-419

Electrical load signal circuit

3

EC-394

Air  conditioner  circuit

2

2

3

3

3

3

3

3

3

3

2

HAC-25

ABS actuator and electric unit (control unit)

4

BRC-36

SYMPTOM

Refer-
ence page

HARD/NO S

TA

R

T/RES

TA

R

T (E

XCP

. HA)

E

N

GINE

 ST

ALL

HES

IT

A

TION/SURGING/FLA

T

 SPOT

S

P

ARK KNOC

K

/DET

O

NA

TI

ON

LACK OF 

POWER/POOR ACCELERA

TION

HIG

H

 IDL

E

/L

OW

 ID

LE

ROUGH IDLE/HUNTING

ID

LING VI

BRA

T

ION

S

LOW/NO RETU

RN 

T

O ID

LE

OVERHEA

T

S

/W

A

TER TEMPERA

T

URE HIG

H

E

XCESSIVE

 FUEL CON

S

UMP

T

ION

E

XCESSIVE

 OIL 

C

O

NSUMP

T

ION

B

A

TTER

Y 

DEAD (UNDER CHARGE)

Warranty symptom code

AA

AB

AC

AD

AE

AF AG AH

AJ

AK

AL

AM HA

ENGINE CONTROL SYSTEM SYMPTOMS

EC-479

< SYMPTOM DIAGNOSIS >

[VK56DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

SYMPTOM

Reference 
page

HARD/NO ST

AR

T/REST

AR

T (EXCP

. 

HA)

E

N

GI

N

E

 ST

AL

L

HESIT

A

TION/S

U

R

GING/F

LA

T SP

OT

SP

ARK KNOCK/DE

T

O

NA

TION

LACK OF POWE

R/POOR

 ACCELERA

TIO

N

HIGH IDL

E/L

OW

 IDL

E

ROUG

H IDLE/HU

NTING

IDL

ING VIBRA

T

ION

SLO

W

/NO RETURN T

O

 IDLE

OVERHEA

T

S/W

A

TE

R

 TEMPERA

T

URE 

HIGH

EXCES

SIVE F

U

EL CONSUMP

T

ION

EXCES

SIVE OI

L CONSUMP

T

IO

N

BA

TTE

R

Y 

DEAD (UN

D

E

R

 CH

A

R

GE)

Warranty symptom code

AA

AB

AC

AD

AE

AF

AG AH

AJ

AK

AL

AM HA

Fuel

Fuel tank

5

5

FL-11

Fuel piping

5

5

5

5

5

5

FL-6

Vapor lock

—

Valve deposit

5

5

5

5

5

5

5

—

Poor fuel (Heavy weight gasoline, 
Low octane)

—

Air

Air duct

5

5

5

5

5

5

EM-25

Air cleaner

EM-25

Air leakage from air duct
(Mass air flow sensor — electric 
throttle control actuator)

5

5

5

5

EM-25

Electric throttle control actuator

EM-26

Air leakage from intake manifold/
Collector/Gasket

EM-26

Cranking

Battery

1

1

1

1

1

1

1

1

PG-74

Generator circuit

CHG-6

Starter circuit

3

STR-8

Signal plate

6

EM-45

Park/Neutral position (PNP) sig-
nal

4

TM-45

Engine

Cylinder head

5

5

5

5

5

5

5

5

EM-68

Cylinder head gasket

4

3

Cylinder block

6

6

6

6

6

6

6

6

4

EM-83

Piston

Piston ring

Connecting rod

Bearing

Crankshaft

Valve 
mecha-
nism

Timing chain

5

5

5

5

5

5

5

5

EM-45

Camshaft

EM-53

Intake valve timing control

EM-53

Intake valve

3

EM-68

Exhaust valve