battery voltage INFINITI QX56 2008 Factory Service Manual

EC-36
< FUNCTION DIAGNOSIS >[VK56DE]
COOLING FAN CONTROL
COOLING FAN CONTROL
DescriptionINFOID:0000000001351873
SYSTEM DESCRIPTION
Cooling Fan Control
*1: The ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to ECM through CAN communication line.
The ECM controls the cooling fan corresponding to the
vehicle speed, engine coolant temperature, refrigerant
pressure, and air conditioner ON signal. The c ontrol system has 2-step control [HI/OFF].
Cooling Fan Operation
SensorInput signal to ECMECM functionActuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
1
Cooling fan
controlIPDM E/R
(Cooling fan relay)
Battery
Battery voltage*
1
Wheel sensorVehicle speed*2
Engine coolant temperature sensor Engine coolant temperature
Air conditioner switch Air conditioner ON signal*
2
Refrigerant pressure sensorRefrigerant pressure
PBIB2060E
Revision: March 2010 2008 QX56

EC-64
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
ItemDIAGNOSTIC TEST MODE
WORK SUP-
PORT SELF-DIAGNOSTIC
RESULTS DATA
MONI-
TOR ACTIVE
TEST DTC & SRT
CONFIRMATION
DTC*1 FREEZE
FRAME
DATA*2 SRT
STATUS DTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS) ×××
Camshaft position sensor (PHASE) ×××
Mass air flow sensor ××
Engine coolant temperature sensor ××××
Air fuel ratio (A/F) sensor 1 ××× ×
Heated oxygen sensor 2 ××× ×
Wheel sensor ×××
Accelerator pedal position sensor ××
Throttle position sensor ×××
Fuel tank temperature sensor ×××
EVAP control system pressure sen-
sor ××
Intake air temperature sensor ×××
Knock sensor ×
Refrigerant pressure sensor ×
Closed throttle position switch (ac-
celerator pedal position sensor sig-
nal) ×
Air conditioner switch ×
Park/neutral position (PNP) signal ××
Stop lamp switch ××
Power steering pressure sensor ××
Battery voltage ×
Load signal ×
Intake valve timing control position
sensor ××
Fuel level sensor ××
Battery current sensor ××
ICC steering switch ××
ASCD steering switch ××
ICC brake switch ××
ASCD brake switch ××
Revision: March 2010 2008 QX56

EC-66
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
*: This function is not necessary in the usual service procedure.
SELF-DIAG RESULTS MODE
Self Diagnostic Item
Regarding items of DTC and 1st trip DTC, refer to
EC-462, "DTC Index".
Freeze Frame Data and 1st Trip Freeze Frame Data
EVAP SYSTEM CLOSECLOSE THE EVAP CANISTER VENT CONTROL VALVE IN
ORDER TO MAKE EVAP SYSTEM CLOSE UNDER THE
FOLLOWING CONDITIONS.
• IGN SW ON
• ENGINE NOT RUNNING
• AMBIENT TEMPERATURE IS ABOVE 0° C (32°F).
• NO VACUUM AND NO HIGH PRESSURE IN EVAP SYS- TEM
• FUEL TANK TEMP. IS MORE THAN 0 °C (32 °F).
• WITHIN 10 MINUTES AFTER STARTING “EVAP SYS- TEM CLOSE”
• WHEN TRYING TO EXECUTE “EVAP SYSTEM CLOSE” UNDER THE CONDITION EXCEPT ABOVE, CONSULT-
III WILL DISCONTINUE IT AND DISPLAY APPROPRI-
ATE INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-III MAY DIS-
PLAY “BATTERY VOLTAGE IS LOW. CHARGE BAT-
TERY”, EVEN IN USING CHARGED BATTERY. When detecting EVAP vapor leak
point of EVAP system
VIN REGISTRATION • IN THIS MODE, VIN IS REGISTERED IN ECMWhen registering VIN in ECM
TARGET IDLE RPM ADJ* • IDLE CONDITION When setting target idle speed
TARGET IGN TIM ADJ* • IDLE CONDITION When adjusting target ignition tim-
ing
WORK ITEM
CONDITION USAGE
Freeze frame data
item* Description
DIAG TROUBLE
CODE
[PXXXX] • The engine control co
mponent part/control system has a trouble code, it is displayed as PXXX X. (Refer to
EC-462, "
DTC Index".)
FUEL SYS-B1 • “Fuel injection system status” at the moment a malfunction is detected is displayed.
• One mode in the following is displayed. Mode2: Open loop due to detected system malfunction
Mode3: Open loop due to driving conditions (power enrichment, deceleration enleanment)
Mode4: Closed loop - using oxygen sensor(s) as feedback for fuel control
Mode5: Open loop - has not yet satisfied condition to go to closed loop
FUEL SYS-B2
CAL/LD VALUE [%] • The calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP
[
° C] or [ °F] • The engine coolant temperature at the moment a malfunction is detected is displayed.
L-FUEL TRM-B1 [%] • “Long-term fuel trim” at the moment a malfunction is detected is displayed. • The long-term fuel trim indicates much more gradual feedback compensation to the base fuel schedule than short-term fuel trim.
L-FUEL TRM-B2 [%]
S-FUEL TRM-B1 [%] • “Short-term fuel trim” at the
moment a malfunction is detected is displayed.
• The short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel sched-
ule.
S-FUEL TRM-B2 [%]
ENGINE SPEED [rpm] • The engine speed at the moment a malfunction is detected is displayed.
VEHICL SPEED
[km/h] or [mph] • The vehicle speed at the moment a malfunction is detected is displayed.
ABSOL TH-P/S
[%] • The throttle valve opening at the moment a malfunction is detected is displayed.
B/FUEL SCHDL
[msec] • The base fuel schedule at the moment a malfunction is detected is displayed.
Revision: March 2010
2008 QX56

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-67
< FUNCTION DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
*: The item is the same as that of 1st trip freeze frame data.
DATA MONITOR MODE
Monitored Item
×
: Applicable
INT/A TEMP SE
[° C] or [ °F] • The intake air temperature at the moment a malfunction is detected is displayed.
INT MANI PRES [kPa] These items are displayed but are not applicable to this model.
FTFMCH1 Freeze frame data
item* Description
Monitored item
[Unit] ECM IN-
PUT SIG- NALS MAIN
SIGNALS Description
Remarks
ENG SPEED [rpm] ×ו Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS) and camshaft position
sensor (PHASE). • Accuracy becomes poor if engine
speed drops below the idle rpm.
• If the signal is interrupted while the en- gine is running, an abnormal value may
be indicated.
MAS A/F SE-B1 [V] ×ו The signal voltage of the mass air flow
sensor is displayed. • When the engine is stopped, a certain
value is indicated.
• When engine is running specification
range is indicated in “SPEC”.
B/FUEL SCHDL
[msec] ו Base fuel schedule indicates the fuel in-
jection pulse width programmed into
ECM, prior to any learned on board cor-
rection. • When engine is running specification
range is indicated in “SPEC”.
A/F ALPHA-B1 [%] ×
• The mean value of the air-fuel ratio feed-back correction factor per cycle is indi-
cated. • When the engine is stopped, a certain
value is indicated.
• When engine is running specification
range is indicated in “SPEC”.
• This data also includes the data for the air-fuel ratio learning control.
A/F ALPHA-B2 [%]
×
COOLAN TEMP/S
[ ° C] or [ °F] ×× • The engine coolant temperature (deter-
mined by the signal voltage of the engine
coolant temperature sensor) is dis-
played. • When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the
ECM is displayed.
A/F SEN1 (B1) [V] ××
• The A/F signal computed from the input
signal of the A/F sensor 1 is displayed.
A/F SEN1 (B2) [V] ×
HO2S2 (B1) [V] ×
• The signal voltage of the heated oxygen
sensor 2 is displayed.
HO2S2 (B2) [V] ×
HO2S2 MNTR (B1)
[RICH/LEAN] ו Display of heated oxygen sensor 2 sig-
nal:
RICH: means the amount of oxygen after
three way catalyst is relatively small.
LEAN: means the amount of oxygen af-
ter three way catalyst is relatively large. • When the engine is stopped, a certain
value is indicated.
HO2S2 MNTR (B2)
[RICH/LEAN] ×
VHCL SPEED SE
[km/h] or [mph] ×ו The vehicle speed computed from the
vehicle speed signal sent from combina-
tion meter is displayed.
BATTERY VOLT [V] ×ו The power supply voltage of ECM is dis-
played.
ACCEL SEN 1 [V] ××
• The accelerator pedal position sensor
signal voltage is displayed. • ACCEL SEN 2 signal is converted by
ECM
in

ternally. Thus, it differs from
ECM terminal voltage signal.
ACCEL SEN 2 [V]
×
Revision: March 2010 2008 QX56

EC-68
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
TP SEN 1-B1 [V]
××
• The throttle position sensor signal volt-
age is displayed. • TP SEN 2-B1 signal is converted by
ECM internally. Thus, it differs from
ECM terminal voltage signal.
TP SEN 2-B1 [V]
×
FUEL T/TMP SE
[ ° C] or [ °F] × • The fuel temperature (determined by the
signal voltage of the fuel tank tempera-
ture sensor) is displayed.
INT/A TEMP SE
[ ° C] or [ °F] ×× • The intake air temperature (determined
by the signal voltage of the intake air
temperature sensor) is indicated.
EVAP SYS PRES
[V] ×
• The signal voltage of EVAP control sys-
tem pressure sensor is displayed.
FUEL LEVEL SE [V] ו The signal voltage of the fuel level sen-
sor is displayed.
START SIGNAL
[ON/OFF] ×ו Indicates start signal status [ON/OFF]
computed by the ECM according to the
signals of engine speed and battery volt-
age. • After starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF] ×ו Indicates idle position [ON/OFF] comput-
ed by ECM according to the accelerator
pedal position sensor signal.
AIR COND SIG
[ON/OFF] ×ו Indicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
P/N POSI SW
[ON/OFF] ××
• Indicates [ON/OFF] condition from the
park/neutral position (PNP) signal.
PW/ST SIGNAL
[ON/OFF] ×ו [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] ×ו 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 lighting switch are OFF.
IGNITION SW
[ON/OFF] ו Indicates [ON/OFF] condition from igni-
tion switch signal.
HEATER FAN SW
[ON/OFF] ×
• Indicates [ON/OFF] condition from heat-
er fan switch signal.
BRAKE SW
[ON/OFF] ו 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 signals. • When the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
IGN TIMING [BT-
DC] ו
Ind
ic
ates 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 val-
ue of the current air flow divided by peak
air flow.
MASS AIRFLOW
[g·m/s] • Indicates the mass air flow computed by
ECM according to the signal voltage of
the mass air flow sensor.
Monitored item
[Unit] ECM IN-
PUT SIG-
NALS MAIN
SIGNALS Description
Remarks
Revision: March 2010 2008 QX56

EC-70
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
A/F S1 HTR (B1)
[%]• A/F sensor 1 heater control value com-
puted by ECM according to the input sig-
nals.
• The current flow to the heater becomes larger as the value increases.
A/F S1 HTR (B2)
[%]
AC PRESS SEN [V]
ו The signal voltage from the refrigerant
pressure sensor is displayed.
VHCL SPEED SE
[km/h] or [mph] ו The vehicle speed computed from the
vehicle speed signal sent from combina-
tion meter is displayed.
SET VHCL SPD
[km/h] or [mph] ×
• The preset vehicle speed is displayed.
MAIN SW
[ON/OFF] ו Indicates [ON/OFF] condition from MAIN
switch signal.
CANCEL SW
[ON/OFF] ×
• Indicates [ON/OFF] condition from CAN-
CEL switch signal.
RESUME/ACC SW
[ON/OFF] ו Indicates [ON/OFF] condition from RE-
SUME/ACCELERATE switch signal.
SET SW
[ON/OFF] ו 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] ו Indicates [ON/OFF] condition of stop
lamp switch signal.
DIST SW
[ON/OFF] • Indicates [ON/OFF] condition from DIS-
TANCE 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 increased to exces-
sively high 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 exces-
sively low compared with the ASCD set
speed, and ASCD operation is cut off.
AT O D M O N I T O R
[ON/OFF] • Indicates [ON/OFF] condition of A/T O/D
according to the input signal from the
TCM.
AT O D C A N C E L
[ON/OFF] • Indicates [ON/OFF] condition of A/T O/D
cancel signal sent from the TCM.
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 determined by the ECM according
to the input signals.
ALT DUTY [%] • Indicates the duty ratio of the power gen-
eration command value. The ratio is cal-
culated by ECM based on the battery
current sensor signal.
BAT CUR SEN [mV] • The signal voltage of battery current sen-
sor is displayed.
Monitored item
[Unit] ECM IN-
PUT SIG-
NALS MAIN
SIGNALS Description
Remarks
Revision: March 2010 2008 QX56

EC-72
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to EC-462, "DTC Index".
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
*: DTC P1442 and P1456 does not apply to JA60 models but appears in DTC Work Support Mode screens.
Generic Scan Tool (GST) FunctionINFOID:0000000001351349
DESCRIPTION
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/T TEMP
SEN • Change the fuel tank temperature using CONSULT-III.
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
V/T ASSIGN AN-
GLE • Engine: Return to the original
trouble condition
• Change intake valve timing using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Harness and connectors
• Intake valve timing control sole-
noid valve
ALTERNATOR
DUTY •Engine: Idle
• Change duty ratio using CON-
SULT-III. Battery voltage changes. • Harness and connectors
• IPDM E/R
•Alternator
TEST ITEM
CONDITION JUDGEMENTCHECK ITEM (REMEDY)
Test mode Test itemCorresponding DTC No. Reference page
EVAPORATIVE
SYSTEM PURG FLOW P0441
P0441EC-219
EVP SML LEAK P0442/P1442* P0442
EC-224P0455EC-259
EVP V/S LEAK P0456/P1456* P0456EC-266
PURG VOL CN/V P1444 P0443EC-231
A/F SEN1 A/F SEN1 (B1) P1276
P0130EC-141A/F SEN1 (B1) P1278/P1279 P0133EC-153
A/F SEN1 (B2) P1286 P0150EC-141
A/F SEN1 (B2) P1288/P1289 P0153EC-153
HO2S2 HO2S2 (B1) P0139
P0139EC-171
HO2S2 (B1) P1146 P0138EC-164
HO2S2 (B1) P1147 P0137EC-159
HO2S2 (B2) P0159 P0159EC-171
HO2S2 (B2) P1166 P0158EC-164
HO2S2 (B2) P1167 P0157EC-159
Revision: March 2010 2008 QX56

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-73
< FUNCTION DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
Generic Scan Tool (OBDII scan tool) complying with SAE J1978 has
8 different functions explained below.
ISO15765-4 is used as the protocol.
The name GST or Generic Scan Tool is used in this service manual.
FUNCTION
INSPECTION PROCEDURE
1. Turn ignition switch OFF.
2. Connect GST to data link connector, which is located under LH
dash panel near the hood opener handle.
SEF139P
Diagnostic test mode Function
Service $01 READINESS TESTS This diagnostic service gains access to current emission-related data values, including an-
alog inputs and outputs, digital inputs and outputs, and system status information.
Service $02 (FREEZE DATA) This diagnostic service gains access to emission-related data value which were stored by
ECM during the freeze frame. For details, refer to
EC-462, "
DTC Index" .
Service $03 DTCs This diagnostic service gains access to emission-related power train trouble codes which
were stored by ECM.
Service $04 CLEAR DIAG INFO This diagnostic service can clear all emission-related diagnostic information. This in-
cludes:
• Clear number of diagnostic trouble codes (Service $01)
• Clear diagnostic trouble codes (Service $03)
• Clear trouble code for freeze frame data (Service $01)
• Clear freeze frame data (Service $02)
• Reset status of system monitoring test (Service $01)
• Clear on board monitoring test results (Service $06 and $07)
Service $06 (ON BOARD TESTS) This diagnostic service accesses the results of on board diagnostic monitoring tests of
specific components/systems that are not continuously monitored.
Service $07 (ON BOARD TESTS) This diagnostic service enables the off board test drive to obtain test results for emission-
related powertrain components/systems that are continuously monitored during normal
driving conditions.
Service $08 —This diagnostic service can close EVAP system in ignition switch ON position (Engine
stopped). When this diagnostic service is performed, the EVAP canister vent control valve
can be closed.
In the following conditions, this diagnostic service cannot function.
• Low ambient temperature
• Low battery voltage
• Engine running
• Ignition switch OFF
• Low fuel temperature
• Too much pressure is applied to EVAP system
Service $09 (CALIBRATION ID) This diagnostic service enables the off-board test device to request specific vehicle infor-
mation such as Vehicle Identification Number (VIN) and Calibration IDs.
BBIA0369E
Revision: March 2010
2008 QX56

POWER SUPPLY AND GROUND CIRCUITEC-83
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
POWER SUPPLY AND GROUND CIRCUIT
Diagnosis ProcedureINFOID:0000000001351355
1.INSPECTION START
Start engine.
Is engine running?
Ye s o r N o
Yes >> GO TO 8.
No >> GO TO 2.
2.CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF and then ON.
2. Check voltage between ECM terminal 109 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• 10A fuse
• Harness for open or short between ECM and fuse
>> Repair harness or connectors.
4.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-86, "
Ground Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace ground connections.
5.CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminals 1, 115, 116 and ground. Refer to Wiring Diagram.
3. Also check harness for short to power. Voltage: Battery voltage
MBIB0015E
BBIA0354E
Continuity should exist.
Revision: March 2010
2008 QX56

EC-84
< COMPONENT DIAGNOSIS >[VK56DE]
POWER SUPPLY AND GROUND CIRCUIT
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors F32, E2
• Harness for open or short between ECM and ground
>> Repair open circuit or short to power in harness or connectors.
7.CHECK ECM POWER SUPPLY CIRCUIT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ON.
3. Check voltage between IPDM E/R terminal 4 and ground with CONSULT-III or tester.
OK or NG
OK >> Go to EC-411, "Diagnosis Procedure" .
NG >> GO TO 8.
8.CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and then OFF.
3. Check voltage between ECM terminals 119, 120 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 13.
NG (Battery voltage does not exist.)>>GO TO 9.
NG (Battery voltage exists for more than a few seconds.)>>GO TO 11 .
9.CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Check voltage between ECM terminal 111 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 10.
NG >> GO TO 11.
10.CHECK ECM POWER SUPPLY CIRCUIT-V
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E119.
3. Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 3. Voltage: Battery voltage
PBIB2063E
Voltage: After turning ignition switch OFF, battery
voltage will exist for a few seconds, then drop
approximately 0V.
PBIB1630E
Voltage: Battery voltage
PBIB1191E
Revision: March 2010 2008 QX56