Infiniti G37 Coupe. Manual - part 486

ON BOARD DIAGNOSTIC (OBD) SYSTEM

EC-125

< FUNCTION DIAGNOSIS >

[VQ37VHR]

C

D

E

F

G

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EC

N

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O

BATTERY VOLT

V

• The power supply voltage of ECM is displayed.

ACCEL SEN 1

V

• The accelerator pedal position sensor signal volt-

age is displayed.

• ACCEL SEN 2 signal is converted by 

ECM internally. Thus, they differs 
from ECM terminal voltage signal.

ACCEL SEN 2

TP SEN 1-B1

V

• The throttle position sensor signal voltage is dis-

played.

• TP SEN 2-B1 signal is converted by 

ECM internally. Thus, they differs 
from ECM terminal voltage signal.

TP SEN 2-B1

FUEL T/TMP SE

°

C or 

°

F

• The fuel temperature (determined by the signal 

voltage of the fuel tank temperature sensor) is 
displayed.

INT/A TEMP SE

°

C or 

°

F

• The intake air temperature (determined by the 

signal voltage of the intake air temperature sen-
sor) is indicated.

EVAP SYS PRES

V

• The signal voltage of EVAP control system pres-

sure sensor is displayed.

FUEL LEVEL SE

V

• The signal voltage of the fuel level sensor is dis-

played.

START SIGNAL

ON/OFF

• Indicates start signal status [ON/OFF] computed 

by the ECM according to the signals of engine 
speed and battery voltage.

• After starting the engine, [OFF] is dis-

played regardless of the starter sig-
nal.

CLSD THL POS

ON/OFF

• Indicates idle position [ON/OFF] computed by 

ECM according to the accelerator pedal position 
sensor signal.

AIR COND SIG

ON/OFF

• Indicates [ON/OFF] condition of the air condition-

er switch as determined by the air conditioner sig-
nal.

P/N POSI SW

ON/OFF

• Indicates [ON/OFF] condition from the park/neu-

tral position (PNP) switch signal.

PW/ST SIGNAL

ON/OFF

• [ON/OFF] condition of the power steering system 

(determined by the signal voltage of the power 
steering pressure sensor signal) is indicated.

LOAD SIGNAL

ON/OFF

• Indicates [ON/OFF] condition from the electrical 

load signal.
ON: Rear window defogger switch is ON and/or 
lighting switch is in 2nd position.
OFF: Both rear window defogger switch and light-
ing switch are OFF.

IGNITION SW

ON/OFF

• Indicates [ON/OFF] condition from ignition switch 

signal.

HEATER FAN SW

ON/OFF

• Indicates [ON/OFF] condition from the heater fan 

switch signal.

BOOST VCUM SW

ON/OFF

• Always a certain value is displayed.
• This item is not efficient for CV36 models.

BRAKE SW

ON/OFF

• Indicates [ON/OFF] condition from the stop lamp 

switch signal.

INJ PULSE-B1

msec

• Indicates the actual fuel injection pulse width 

compensated by ECM according to the input sig-
nals.

• When the engine is stopped, a certain 

computed value is indicated.

INJ PULSE-B2

IGN TIMING

BTDC

• Indicates the ignition timing computed by ECM 

according to the input signals.

• When the engine is stopped, a certain 

value is indicated.

CAL/LD VALUE

%

• “Calculated load value” indicates the value of the 

current air flow divided by peak air flow.

MASS AIRFLOW

g·m/s

• Indicates the mass air flow computed by ECM ac-

cording to the signal voltage of the mass air flow 
sensor.

Monitored item

Unit

Description

Remarks

EC-126

< FUNCTION DIAGNOSIS >

[VQ37VHR]

ON BOARD DIAGNOSTIC (OBD) SYSTEM

PURG VOL C/V

%

• Indicates the EVAP canister purge volume con-

trol solenoid valve control value computed by the 
ECM according to the input signals.

• The opening becomes larger as the value in-

creases.

INT/V SOL (B1)

%

• The control value of the intake valve timing con-

trol solenoid valve (determined by ECM accord-
ing to the input signals) is indicated.

• The advance angle becomes larger as the value 

increases.

INT/V SOL (B2)

TP SEN 1-B2

V

• The throttle position sensor signal voltage is dis-

played.

• TP SEN 2-B2 signal is converted by 

ECM internally. Thus, they differs 
from ECM terminal voltage signal.

TP SEN 2-B2

AIR COND RLY

ON/OFF

• The air conditioner relay control condition (deter-

mined by ECM according to the input signals) is 
indicated.

FUEL PUMP RLY

ON/OFF

• Indicates the fuel pump relay control condition 

determined by ECM according to the input sig-
nals.

VENT CONT/V

ON/OFF

• The control condition of the EVAP canister vent 

control valve (determined by ECM according to 
the input signals) is indicated.
ON: Closed
OFF: Open

THRTL RELAY

ON/OFF

• Indicates the throttle control motor relay control 

condition determined by the ECM according to 
the input signals.

HO2S2 HTR (B1)

ON/OFF

• Indicates [ON/OFF] condition of heated oxygen 

sensor 2 heater determined by ECM according to 
the input signals.

HO2S2 HTR (B2)

I/P PULLY SPD

rpm

• Indicates the engine speed computed from the 

turbine revolution sensor signal.

VEHICLE SPEED

km/h or mph

• The vehicle speed computed from the vehicle 

speed signal sent from TCM is displayed.

IDL A/V LEARN

YET/CMPLT

• Display the condition of Idle Air Volume Learning

YET: Idle air volume learning has not been per-
formed yet.
CMPLT: Idle air volume learning has already 
been performed successfully.

ENG OIL TEMP

°

C or 

°

F

• The engine oil temperature (determined by the 

signal voltage of the engine oil temperature sen-
sor) is displayed.

TRVL AFTER MIL

km or mile

• Distance traveled while MIL is activated.

A/F S1 HTR (B1)

%

• Air fuel ratio (A/F) sensor 1 heater control value 

computed by ECM according to the input signals.

• The current flow to the heater becomes larger as 

the value increases.

A/F S1 HTR (B2)

AC PRESS SEN

V

• The signal voltage from the refrigerant pressure 

sensor is displayed.

VHCL SPEED SE

km/h or mph

• The vehicle speed computed from the vehicle 

speed signal sent from combination meter is dis-
played.

SET VHCL SPD

km/h or mph

• The preset vehicle speed is displayed.

MAIN SW

ON/OFF

• Indicates [ON/OFF] condition from MAIN switch 

signal.

CANCEL SW

ON/OFF

• Indicates [ON/OFF] condition from CANCEL 

switch signal.

Monitored item

Unit

Description

Remarks

ON BOARD DIAGNOSTIC (OBD) SYSTEM

EC-127

< FUNCTION DIAGNOSIS >

[VQ37VHR]

C

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RESUME/ACC SW

ON/OFF

• Indicates [ON/OFF] condition from RESUME/AC-

CELERATE switch signal.

SET SW

ON/OFF

• Indicates [ON/OFF] condition from SET/COAST 

switch signal.

BRAKE SW1

ON/OFF

• Indicates [ON/OFF] condition from ASCD brake 

switch signal.

BRAKE SW2

ON/OFF

• Indicates [ON/OFF] condition of stop lamp switch 

signal.

DIST SW

ON/OFF

• Indicates [ON/OFF] condition from DISTANCE 

switch signal.

VHCL SPD CUT

NON/CUT

• Indicates the vehicle cruise condition.

NON: Vehicle speed is maintained at the ASCD 
set speed.
CUT: Vehicle speed decreased to excessively 
low compared with the ASCD set speed, and 
ASCD operation is cut off.

LO SPEED CUT

NON/CUT

• Indicates the vehicle cruise condition.

NON: Vehicle speed is maintained at the ASCD 
set speed.
CUT: Vehicle speed decreased to excessively 
low, and ASCD operation is cut off.

AT OD MONITOR

ON/OFF

• Indicates [ON/OFF] condition of A/T O/D accord-

ing to the input signal from the TCM.

• For M/T models, always “OFF” is dis-

played.

AT OD CANCEL

ON/OFF

• Indicates [ON/OFF] condition of A/T O/D cancel 

request signal.

• For M/T models, always “OFF” is dis-

played.

CRUISE LAMP

ON/OFF

• Indicates [ON/OFF] condition of CRUISE lamp 

determined by the ECM according to the input 
signals.

SET LAMP

ON/OFF

• Indicates [ON/OFF] condition of SET lamp deter-

mined by the ECM according to the input signals.

BAT CUR SEN

mV

• The signal voltage of battery current sensor is 

displayed.

ALT DUTY SIG

ON/OFF

• The control condition of the power generation 

voltage variable control (determined by ECM ac-
cording to the input signals) is indicated.
ON: Power generation voltage variable control is 
active.
OFF: Power generation voltage variable control 
is inactive.

A/F ADJ-B1

—

• Indicates the correction of factor stored in ECM. 

The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and 
the air-fuel ratio calculated from A/F sensor 1 sig-
nal.

A/F ADJ-B2

FAN DUTY

%

• Indicates a command value for cooling fan. The 

value is calculated by ECM based on input sig-
nals.

AC EVA TEMP

°

C or 

°

F

• Indicates A/C evaporator temperature sent from 

“unified meter and A/C amp.”.

AC EVA TARGET

°

C or 

°

F

• Indicates target A/C evaporator temperature sent 

from “unified meter and A/C amp.”.

ALTDUTY

%

• Indicates the duty ratio of the power generation 

command value. The ratio is calculated by ECM 
based on the battery current sensor signal.

Monitored item

Unit

Description

Remarks

EC-128

< FUNCTION DIAGNOSIS >

[VQ37VHR]

ON BOARD DIAGNOSTIC (OBD) SYSTEM

NOTE:

Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.

ACTIVE TEST MODE

Test Item

VVEL SEN LEARN-
B1

V

• Indicates the VVEL learning value.

VVEL SEN LEARN-
B2

VVEL POSITION 
SEN-B1

V

• The VVEL control shaft position sensor signal 

voltage is displayed.

VVEL POSITION 
SEN-B2

VVEL TIM-B1

deg

• Indicates [deg] of VVEL control shaft angle. 

VVEL TIM-B2

VVEL LEARN

YET/DONE

• Display the condition of VVEL learning

YET: VVEL learning has not been performed yet.
CMPLT: VVEL learning has already been per-
formed successfully.

Monitored item

Unit

Description

Remarks

TEST ITEM

CONDITION

JUDGEMENT

CHECK ITEM (REMEDY)

VENT CON-
TROL/V

• Ignition switch: ON (Engine 

stopped)

• Turn solenoid valve ON and OFF 

with the CONSULT-III and listen 
to operating sound.

Solenoid valve makes an operating 
sound.

• Harness and connectors
• Solenoid valve

ENG COOLANT 
TEMP

• Engine: Return to the original 

trouble condition

• Change the engine coolant tem-

perature using CONSULT-III.

If trouble symptom disappears, see 
CHECK ITEM.

• Harness and connectors
• Engine coolant temperature sen-

sor

• Fuel injector

FUEL INJEC-
TION

• Engine: Return to the original 

trouble condition

• Change the amount of fuel injec-

tion using CONSULT-III.

If trouble symptom disappears, see 
CHECK ITEM.

• Harness and connectors
• Fuel injector
• Air fuel ratio (A/F) sensor 1

FUEL/T TEMP 
SEN

• Change the fuel tank temperature using CONSULT-III.

PURG VOL 
CONT/V

• Engine: After warming up, run en-

gine at 1,500 rpm.

• Change the EVAP canister purge 

volume control solenoid valve 
opening percent using CON-
SULT-III.

Engine speed changes according to 
the opening percent.

• Harness and connectors
• Solenoid valve

FUEL PUMP RE-
LAY

• Ignition switch: ON (Engine 

stopped)

• Turn the fuel pump relay ON and 

OFF using CONSULT-III and lis-
ten to operating sound.

Fuel pump relay makes the operat-
ing sound.

• Harness and connectors
• Fuel  pump  relay

IGNITION TIM-
ING

• Engine: Return to the original 

trouble condition

• Timing light: Set
• Retard the ignition timing using 

CONSULT-III.

If trouble symptom disappears, see 
CHECK ITEM.

• Perform Idle Air Volume Learning.

FAN DUTY CON-
TROL*

• Ignition  switch:  ON
• Change duty ratio using CON-

SULT-III.

Cooling fan speed changes.

• Harness and connectors
• Cooling fan motor
• Cooling fan relay
• Cooling fan control module
• IPDM E/R