Infiniti QX56 (Z62). Manual - part 608

EC-410

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P1423, P1424 COLD START CONTROL

P1423, P1424 COLD START CONTROL

Description

INFOID:0000000006288266

ECM controls fuel injection timing and fuel injection quantity when engine is started with the engine cold.
This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.

DTC Logic

INFOID:0000000006288267

DTC DETECTION LOGIC

NOTE:
• If DTC P1423 or P1424 is displayed with other DTC, first perform the trouble diagnosis for other DTC.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

 WITH CONSULT-III

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Select “DATA MONITOR” mode with CONSULT-III.

4.

Check that “COOLAN TEMP/S”.

-

If it is between 5

°

C (41

°

F) and 40

°

C (104

°

F) go to the following steps.

-

If it is below 5

°

C (41

°

F) warm engine up to more than 5

°

C (41

°

F) and retry from step 1.

-

If it is above 40

°

C (104

°

F) cool engine down to less than 40

°

C (104

°

F) and retry from step 1.

5.

Start engine and let it idle for 5 minutes.

6.

Check 1st trip DTC.

 WITH GST

Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-410, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006288268

1.

INSPECTION START

1.

Turn ignition switch ON.

2.

Erase DTC.

3.

Perform DTC confirmation procedure. Refer to 

EC-410, "DTC Logic"

.

4.

Check 1st trip DTC.

Is the 1st trip DTC P1423 or P1424 displayed again?

YES

>> GO TO 2.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P1423

COLD START CONTROL
(Cold start emission reduction 
strategy monitoring)

ECM does not control fuel injection timing prop-
erly when engine is started with the engine cold.

ECM

P1424

COLD START CONTROL
(Cold start emission reduction 
strategy monitoring)

ECM does not control fuel injection quantity 
properly when engine is started with with the en-
gine cold.

P1423, P1424 COLD START CONTROL

EC-411

< DTC/CIRCUIT DIAGNOSIS >

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C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

NO

>> INSPECTION END

2.

REPLACE ECM

Replace ECM. Refer to 

EC-535, "Removal and Installation"

.

>> INSPECTION END

EC-412

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P1550 BATTERY CURRENT SENSOR

P1550 BATTERY CURRENT SENSOR

DTC Logic

INFOID:0000000006217919

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 8 V or more at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and let it idle for at least 10 seconds.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-412, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217920

1.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT-I

1.

Disconnect battery current sensor harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between battery current sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 8.

NO

>> GO TO 2.

2.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT-II

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P1550

BAT CURRENT SENSOR
(Battery current sensor cir-
cuit range/performance)

The output voltage of the battery 
current sensor remains within 
the specified range while engine 
is running.

• Harness or connectors

(Battery current sensor circuit is open or shorted.)
(Accelerator pedal position sensor 2 circuit is shorted.)
[Camshaft position sensor (bank 1) circuit is shorted.]
(Crankshaft position sensor circuit is shorted.)
(Refrigerant pressure sensor circuit is shorted.)
(EVAP control system pressure sensor circuit is short-
ed.)

• Battery current sensor
• Accelerator pedal position sensor
• Camshaft position sensor (bank 1)
• Crankshaft position sensor
• Refrigerant pressure sensor
• EVAP control system pressure sensor

Battery current sensor

Ground

Voltage (V)

Connector

Terminal

E63

2

Ground

Approx. 5

P1550 BATTERY CURRENT SENSOR

EC-413

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

3.

Check the continuity between battery current sensor harness connector and ECM harness connector.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.
• Harness for open between battery current sensor and ECM
• Loose or poor connection for each connector and harness

>> Repair open circuit.

4.

CHECK SENSOR POWER SUPPLY CIRCUIT

Check harness for short to power and short to ground, between the following terminals.

Is the inspection result normal?

YES

>> GO TO 5.

NO

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

5.

CHECK COMPONENTS

Check the following.
• Crankshaft position sensor (Refer to 

EC-301, "Component Inspection (Crankshaft Position Sensor)"

.)

• Camshaft position sensor (bank 1) (Refer to 

EC-306, "Component Inspection (Camshaft Position Sensor)"

.)

• EVAP control system pressure sensor (Refer to 

EC-520, "Component Function Check"

.)

• Refrigerant pressure sensor (Refer to 

EC-520, "Component Function Check"

.)

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace malfunctioning component.

6.

CHECK APP SENSOR

Refer to 

EC-470, "Component Inspection (Accelerator Pedal Position Sensor)"

.

Is the inspection result normal?

YES

>> GO TO 13.

NO

>> GO TO 7.

7.

REPLACE ACCELERATOR PEDAL ASSEMBLY

Replace accelerator pedal assembly. Refer to 

ACC-3, "MODELS WITHOUT DISTANCE CONTROL ASSIST

SYSTEM : Removal and Installation"

 (Without distance control assist system) or 

ACC-4, "MODELS WITH

DISTANCE CONTROL ASSIST SYSTEM : Removal and Installation"

 (With distance control assist system).

>> INSPECTION END

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E63

2

E80

133

Existed

ECM

Sensor

Connector

Terminal

Name

Connector

Terminal

F110

76

Crankshaft position sensor

F74

1

77

Camshaft position sensor (bank 1)

F84

1

E80

133

EVAP control system pressure sen-
sor

C17

3

Refrigerant pressure sensor

E77

1

131

APP sensor 2 (Without ICC)

E110

1

APP sensor 2 (with ICC)

E67

9