2010 INFINITI QX56 Ignition switch

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] • 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] • 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] • 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 val-
ue of th

e 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: April 20092010 QX56

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-71
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*: 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-459, "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
TEST ITEM CONDITION JUDGEMENTCHECK ITEM (REMEDY)
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
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.
POWER BAL-
ANCE • Engine: After warming up, idle the
engine.
• A/C switch: OFF
• Selector lever: P or N
• Cut off each injector signal one at a time using CONSULT-III. Engine runs rough or dies.
• Harness and connectors
• Compression
• Fuel injector
• Power transistor
•Spark plug
• Ignition coil
COOLING FAN* • Ignition switch: ON
• Turn the cooling fan HI and OFF
using CONSULT-III. Cooling fan moves and stops. • Harness and connectors
• Cooling fan motor
•IPDM E/R
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 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
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 •
E
ngine: Idle
• Change duty ratio using CON- SULT-III. Battery voltage changes. • Harness and connectors
•IPDM E/R
• Alternator
Revision: April 20092010 QX56

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-73
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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.
3. Turn ignition switch ON.
4. Enter the program according to instruction on the screen or in the operation manual.
(*: Regarding GST screens in this section, sample screens are
shown.)
5. Perform each diagnostic service according to each service pro- cedure.
For further information, see th e GST Operation Manual of
the tool maker.
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.
Diagnostic test mode
Function
BBIA0369E
SEF398S
SEF416S
Revision: April 20092010 QX56

EC-82
< COMPONENT DIAGNOSIS >[VK56DE]
POWER SUPPLY AND GROUND CIRCUIT
POWER SUPPLY AND GROUND CIRCUIT
Diagnosis ProcedureINFOID:0000000005149085
1.INSPECTION START
Start engine.
Is engine running?
Ye s o r N o
Ye s > > G O T O 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 (No. 59)
• 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-85, "
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: April 20092010 QX56

POWER SUPPLY AND GROUND CIRCUITEC-83
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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-407, "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 0 V.
PBIB1630E
Voltage: Battery voltage
PBIB1191E
Revision: April 20092010 QX56

EC-84
< COMPONENT DIAGNOSIS >[VK56DE]
POWER SUPPLY AND GROUND CIRCUIT
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 13.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
11 .CHECK ECM POWER SUPPLY CIRCUIT-VI
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E119.
3. Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 12.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
12.CHECK 20 A FUSE
1. Disconnect 20 A fuse from IPDM E/R.
2. Check 20 A fuse (No. 53).
OK or NG
OK >> GO TO 16.
NG >> Replace 20 A fuse.
13.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground three screws on the body. Refer to EC-85, "
Ground Inspection".
OK or NG
OK >> GO TO 14.
NG >> Repair or replace ground connections.
14.CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II
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.
OK or NG
OK >> GO TO 16.
NG >> GO TO 15.
15.DETECT MALFUNCTIONING PART Continuity should exist.
Continuity should exist.
BBIA0354E
Continuity should exist.
Revision: April 20092010 QX56

EC-86
< COMPONENT DIAGNOSIS >[VK56DE]
U0101 CAN COMM CIRCUIT
U0101 CAN COMM CIRCUIT
DescriptionINFOID:0000000005157950
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 s
peed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CA N communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
On Board Diagn osis LogicINFOID:0000000005157951
This self-diagnosis has the one trip detection logic.
DTC Confirmation ProcedureINFOID:0000000005157952
1. Turn ignition switch ON and wait at least 3 seconds.
2. Check DTC.
3. If DTC is detected, go to EC-86, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005157953
Go to LAN-44, "CAN Communication Signal Chart".
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
U0101
0101 Lost communication with
TCM When ECM is not transmitting or receiving CAN
communication signal of OBD (emission-related
diagnosis) with TCM for 2 seconds or more. • CAN communication line between
TCM and ECM
(CAN communication line is open or
shorted)
Revision: April 20092010 QX56

U1001 CAN COMM CIRCUITEC-87
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U1001 CAN COMM CIRCUIT
DescriptionINFOID:0000000005149087
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. Many elec-
tronic control units are equipped onto a vehicle, and each
control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
On Board Diagnosis LogicINFOID:0000000005149088
MIL will not illuminate for this self-diagnosis.
DTC Confirmation ProcedureINFOID:0000000005149089
1. Turn ignition switch ON and wait at least 3 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-87, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149090
Go to LAN-44, "CAN Communication Signal Chart".
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
U1001
1001 CAN communication line When ECM is not transmitting or receiving CAN
communication signal other than OBD (emis-
sion related diagnosis) for 2 seconds or more. • Harness or connectors
(CAN communication line is open or
shorted)
Revision: April 20092010 QX56