2008 INFINITI QX56 sensor

P0643 SENSOR POWER SUPPLYEC-293
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P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000001351684
This self-diagnosis has the on
e trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000001351685
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
WITH CONSULT-III
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-293, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351687
1.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
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643 Sensor power supply circuit
short ECM detects a voltage of power source
for sensor is excessively low or high. • Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Battery current sensor circuit is shorted.)
(Refrigerant pressure se nsor circuit is short-
ed.)
(EVAP control system pressure sensor circuit
is shorted.)
• Accelerator pedal position sensor
• Power steering pressure sensor
• Refrigerant pressure sensor
• EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
BBIA0354E
Revision: March 2010 2008 QX56

EC-294
< COMPONENT DIAGNOSIS >[VK56DE]
P0643 SENSOR POWER SUPPLY
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with
CONSULT-III or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUITS
Check harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4.CHECK COMPONENTS
Check the following.
• EVAP control system pressure sensor (Refer to EC-253, "
Component Inspection".)
• Power steering pressure sensor (Refer to EC-288, "
Component Inspection".)
• Battery current sensor (Refer to EC-318, "
Component Inspection".)
• Refrigerant pressure sensor
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5.CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-384, "
Component Inspection".
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
JMBIA0601ZZ
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3
EC-439, "
Wiring Diagram - ENGINE
CONTROL SYSTEM -"
49Refrigerant pressure sensor terminal 1
Battery current sensor terminal 1
68 Power steering pressure sensor terminal 1
90 APP sensor terminal 7
Revision: March 2010 2008 QX56

P0643 SENSOR POWER SUPPLYEC-295
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6.REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace accelerator pedal position assembly.
2. Perform EC-18, "
Accelerator Pedal Released Position Learning".
3. Perform EC-18, "
Throttle Valve Closed Position Learning".
4. Perform EC-18, "
Idle Air Volume Learning".
>> INSPECTION END
7.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Revision: March 2010 2008 QX56

P1140, P1145 IVT CONTROL POSITION SENSOR
EC-299
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P1140, P1145 IVT CONTROL POSITION SENSOR
Component DescriptionINFOID:0000000001351695
Intake valve timing control position sensors are located in the front of
cylinder heads in both bank 1 and bank 2.
This sensor uses a Hall IC.
The cam position is determined by the intake camshaft sprocket con-
cave (in four places). The ECM provides feedback to the intake valve
timing control for appropriate target valve open-close timing accord-
ing to drive conditions based on detected cam position.
On Board Diagnosis LogicINFOID:0000000001351697
DTC Confirmation ProcedureINFOID:0000000001351698
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Maintain the following conditions for at least 10 seconds.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to
EC-299, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351700
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
SEF359Z
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P1140
11 4 0
(Bank 1)
Intake valve timing control
position sensor circuit An excessively high or low voltage from the
sensor is sent to ECM. • Harness or connectors
(Intake valve timing control position
sensor circuit is open or shorted)
• Intake valve timing control position sensor
• Crankshaft position sensor (POS)
• Camshaft positi on sensor (PHASE)
• Accumulation of debris to the signal pick-up portion of the camshaft sprock-
et
P1145
11 4 5
(Bank 2)
ENG SPEED
More than idle speed
Selector lever P or N position
Revision: March 2010 2008 QX56

EC-300
< COMPONENT DIAGNOSIS >[VK56DE]
P1140, P1145 IVT CONTROL POSITION SENSOR
Refer to EC-86, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE VALVE TIMING CONTROL PO SITION SENSOR POWER SUPPLY CIRCUIT
1. Disconnect intake valve timing control position sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between intake valve timing control position sen- sor terminal 3 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.
• Harness connectors E2, F32
• Harness for open or short between intake valve timing control position sensor and IPDM E/R
• Harness for open or short between intake valve timing control position sensor and ECM
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK INTAKE VALVE TIMING CONTROL POSI TION SENSOR GROUND CIRCUIT FOR OPEN AND
SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between intake valve timing control position sensor terminal 1 and ground.
Refer to Wiring Diagram.
BBIA0354E
1. Intake valve timing control position
sensor (bank 2) 2. Intake valve timing control solenoid
valve (bank 2) 3. Drive belt
4. Radiator hose 5. Intake valve timing control solenoid
valve (bank 1) 6. Intake valve timing control position
sensor (bank 1)
Voltage: Battery voltage
BBIA0771E
SEF509Y
Revision: March 2010 2008 QX56

P1140, P1145 IVT CONTROL POSITION SENSOR
EC-301
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3. Also check harness for short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E2, F32
• Harness for open or short between intake valve timing control position sensor and ground
>> Repair open circuit or short to power in harness or connectors.
6.CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR INPUT SIGNAL CIRCUIT FOR OPEN
AND SHORT1. Disconnect ECM harness connector.
2. Check harness continuity between the following; ECM terminal 72 and intake valve timing control position sensor (Bank 1) terminal 2 or
ECM terminal 53 and intake valve timing contro l position sensor (Bank 2) terminal 2.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR
Refer to EC-302, "
Component Inspection".
OK or NG
OK >> GO TO 8.
NG >> Replace malfunctioning intake valve timing control position sensor. Refer to EC-501
.
8.CHECK CRANKSHAFT POSITION SENSOR (POS)
Refer to EC-209, "
Component Inspection".
OK or NG
OK >> GO TO 9.
NG >> Replace crankshaft position sensor (POS).
9.CHECK CAMSHAFT POSITI ON SENSOR (PHASE)
Refer to EC-213, "
Component Inspection".
OK or NG
OK >> GO TO 10.
NG >> Replace camshaft position sensor (PHASE). Refer to EC-501
.
10.CHECK CAMSHAFT SPROCKET
Check accumulation of debris to the signal pick- up portion of the camshaft sprocket. Refer to EM-62, "
Inspec-
tion after Installation".
OK or NG
OK >> GO TO 11.
NG >> Remove debris and clean the signal pick-up cutout of camshaft sprocket.
11 .CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
Continuity should exist.
Continuity should exist.
Revision: March 2010
2008 QX56

EC-302
< COMPONENT DIAGNOSIS >[VK56DE]
P1140, P1145 IVT CONTROL POSITION SENSOR
>>
INSPECTION END
Component InspectionINFOID:0000000001351701
INTAKE VALVE TIMING CONTROL POSITION SENSOR
1. Disconnect intake valve timing control position sensor harness connector.
2. Loosen the fixing bolt of the sensor.
3. Remove the sensor.
4. Visually check the sensor for chipping.
5. Check resistance as shown below.
6. If NG, replace intake valve timing control position sensor. Refer
to EC-501
.
SEF362Z
Terminal No. (Polarity) Resistance Ω [at 25 °C (77 °F)]
3 (+) - 1 (-) Except 0 or ∞
2 (+) - 1 (-)
3 (+) - 2 (-)
PBIB0194E
Revision: March 2010 2008 QX56

P1148, P1168 CLOSED LOOP CONTROLEC-303
< COMPONENT DIAGNOSIS > [VK56DE]
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P1148, P1168 CLOSED LOOP CONTROL
On Board Diagnosis LogicINFOID:0000000001351703
These self-diagnoses have the on
e trip detection logic.
DTC P1148 or P1168 is displayed with another DTC for air fuel ratio (A/F) sensor 1.
Perform the trouble diagnosis for the corresponding DTC.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1148
11 4 8
(Bank 1) Closed loop control
function The closed loop control function for bank 1 does
not operate even when vehicle is driving in the
specified condition.
• Harness or connectors
[The air fuel ratio (A/F) sensor 1 circuit is
open or shorted.]
• Air fuel ratio (A/F) sensor 1
• Air fuel ratio (A/F) sensor 1 heater
P1168
11 6 8
(Bank 2) The closed loop control function for bank 2 does
not operate even when vehicle is driving in the
specified condition.
Revision: March 2010
2008 QX56