Infiniti G37 Coupe. Manual - part 492

U1024 CAN COMM CIRCUIT

EC-149

< COMPONENT DIAGNOSIS >

[VQ37VHR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

U1024 CAN COMM CIRCUIT

Description

INFOID:0000000001910712

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. ECM and
VVEL control module are connected with two communication lines (CAN H line and CAN L line) and transmit/
receive data. ECM shares information and links with the VVEL control module during operation.

DTC Logic

INFOID:0000000001736736

DTC DETECTION LOGIC

NOTE:
If DTC U1024 is displayed with DTC U1011, first perform the trouble diagnosis for DTC U1011. 
Refer to 

EC-148, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING 

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Turn ignition switch ON and wait at least 3 seconds.

2.

Check DTC.

Is DTC detected?

YES

>> Go to 

EC-149, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001736743

1.

CHECK VVEL CAN COMMUNICATION CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Disconnect VVEL control module harness connector.

4.

Check the continuity between ECM harness connector and VVEL control module harness connector.

5.

Also check harness for short to ground and power.

Is the inspection result normal?

YES

>> GO TO 2.

NO

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

2.

CHECK INTERMITTENT INCIDENT

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

U1024

VVEL CAN communication

• When VVEL control module cannot 

transmit/receive can communication 
signal from ECM.

• When detecting error during the ini-

tial diagnosis of CAN controller of 
VVEL control module.

• Harness or connectors

(CAN communication line is open or 
shorted)

• ECM
• VVEL control module

ECM

VVEL control module

Continuity

Connector

Terminal

Connector

Terminal

F102

54

E15

24

Existed

55

11

EC-150

< COMPONENT DIAGNOSIS >

[VQ37VHR]

U1024 CAN COMM CIRCUIT

Refer to 

GI-38, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace.

3.

REPLACE VVEL CONTROL MODULE

1.

Replace VVEL control module.

2.

Go to 

EC-17, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (VVEL CONTROL MOD-

ULE) : Special Repair Requirement"

.

>> GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE

 With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “SELF-DIAG RESULTS” mode with CONSULT-III.

3.

Touch “ERASE”.

4.

Perform DTC Confirmation Procedure.
See 

EC-149, "DTC Logic"

.

 With GST

1.

Turn ignition switch ON.

2.

Select Service $04 with GST.

3.

Perform DTC Confirmation Procedure.
See 

EC-149, "DTC Logic"

.

Is the DTC U1024 displayed again?

YES

>> GO TO 5.

NO >> INSPECTION 

END

5.

REPLACE ECM

1.

Replace ECM.

2.

Go to 

EC-16, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM) : Special Repair

Requirement"

.

>> INSPECTION END

P0011, P0021 IVT CONTROL

EC-151

< COMPONENT DIAGNOSIS >

[VQ37VHR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0011, P0021 IVT CONTROL

DTC Logic

INFOID:0000000001733977

DTC DETECTION LOGIC

NOTE:
• If DTC P0011 or P0021 is displayed with DTC P0075 or P0081, first perform the trouble diagnosis for

DTC P0075, P0081. Refer to 

EC-162, "DTC Logic"

.

• If DTC P0011 or P0021 is displayed with DTC P0524, first perform the trouble diagnosis for DTC

P0524. Refer to 

EC-343, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next test. 
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 between 10V and 16V at
idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE-I

With CONSULT-III

1.

Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.

2.

Start engine and warm it up to the normal operating temperature.

3.

Maintain the following conditions for at least 6 consecutive seconds. Hold the accelerator pedal as steady
as possible.

CAUTION:

Always drive at a safe speed.

4.

Stop vehicle with engine running and let engine idle for 10 seconds.

5.

Check 1st trip DTC.

With GST

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

YES

>> Go to 

EC-152, "Diagnosis Procedure"

DTC No.

Trouble diagnosis 

name

Detecting condition

Possible cause

P0011

Intake valve timing 
control performance 
(bank 1)

There is a gap between angle of target and 
phase-control angle degree.

• Crankshaft position sensor (POS)
• Camshaft position sensor (PHASE)
• Intake valve control solenoid valve
• Accumulation of debris to the signal pick-up 

portion of the camshaft

• Timing chain installation
• Foreign matter caught in the oil groove for in-

take valve timing control

P0021

Intake valve timing 
control performance 
(bank 2)

VHCL SPEED SE

100 - 120 km/h (63 - 75 mph)

ENG SPEED

1,200 - 2,000 rpm

COOLAN TEMP/S

More than 60

°

C (140

°

F)

B/FUEL SCHDL

More than 7.3 msec

Selector lever

D position (A/T)
5th position (M/T)

EC-152

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0011, P0021 IVT CONTROL

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE-II

With CONSULT-III

1.

Select “DATA MONITOR” mode with CONSULT-III.

2.

Maintain the following conditions for at least 20 consecutive seconds.

CAUTION:

Always drive at a safe speed.

3.

Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT-III” above.

Is 1st trip DTC detected?

YES

>> Go to 

EC-152, "Diagnosis Procedure"

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001733978

1.

CHECK OIL PRESSURE WARNING LAMP

1.

Start engine.

2.

Check oil pressure warning lamp and confirm it is not illumi-
nated.

Is oil pressure warning lamp illuminated?

YES

>> Go to 

LU-6, "Inspection"

.

NO

>> GO TO 2.

2.

CHECK INTAKE VALVE TIMING CONTROL SOLENOID VALVE

Refer to 

EC-153, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Replace malfunctioning intake valve timing control solenoid valve.

3.

CHECK CRANKSHAFT POSITION SENSOR (POS)

Refer to 

EC-267, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace crankshaft position sensor (POS).

4.

CHECK CAMSHAFT POSITION SENSOR (PHASE)

Refer to 

EC-271, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Replace malfunctioning camshaft position sensor (PHASE).

ENG SPEED

1,700 - 3,175 rpm (A constant rotation is maintained.)

COOLAN TEMP/S

More than 70

°

C (158

°

F)

Selector lever

1st or 2nd position

Driving location uphill

Driving vehicle uphill
(Increased engine load will help maintain the driving 
conditions required for this test.)

PBIA8559J