INFINITI QX56 2006 Factory Service Manual

EC-460Revision: November 2009
DTC P0643 SENSOR POWER SUPPLY
2006 QX56
DTC P0643 SENSOR POWER SUPPLYPFP:18919
On Board Diagnosis LogicUBS00H9B
This self-diagnosis has the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H9C
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-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR ” mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. If DTC is detected, go to EC-463, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
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.)
(Refrigerant pressure sensor circuit is
shorted.)
(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.
SEF058Y

DTC P0643 SENSOR POWER SUPPLYEC-461
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Revision: November 2009 2006 QX56
Wiring DiagramUBS00H9D
BBWA2123E

EC-462Revision: November 2009
DTC P0643 SENSOR POWER SUPPLY
2006 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
48 SB Sensor power supply
(EVAP control system
pressure sensor)
[Ignition switch: ON]
Approximately 5V
49 R/Y Sensor power supply
(Refrigerant pressure
sensor) [Ignition switch: ON]
Approximately 5V
68 W/L Sensor power supply
(Power steering pressure
sensor) [Ignition switch: ON]
Approximately 5V
82 B/R Sensor ground
(APP sensor 1) [Engine is running]

Warm-up condition

Idle speed
Approximately 0V
83 G/W Sensor ground
(APP sensor 2) [Engine is running]

Warm-up condition

Idle speed
Approximately 0V
90 L Sensor power supply
(APP sensor 1)
[Ignition switch: ON]
Approximately 5V
91 W/R Sensor power supply
(APP sensor 2) [Ignition switch: ON]
Approximately 5V
98 G/R Accelerator pedal position
sensor 2 [Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully released
0.25 - 0.50V
[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully depressed 2.0 - 2.5V
106 BR/W Accelerator pedal position
sensor 1 [Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully released
0.5 - 1.0V
[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully depressed 4.2 - 4.8V

DTC P0643 SENSOR POWER SUPPLYEC-463
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Revision: November 2009 2006 QX56
Diagnostic ProcedureUBS00H9E
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
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-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
BBIA0354E
BBIA0361E
Voltage: Approximately 5V
PBIB2070E

EC-464Revision: November 2009
DTC P0643 SENSOR POWER SUPPLY
2006 QX56
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-410, "Component Inspection" .)

Power steering pressure sensor (Refer to EC-452, "Component Inspection" .)

Refrigerant pressure sensor (Refer to EC-630, "REFRIGERANT PRESSURE SENSOR" .)
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5. CHECK ACCELERATOR PEEDAL POSITION SENSOR
Refer to EC-574, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6. REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace accelerator pedal position assembly.
2. Perform EC-78, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-78, "
Throttle Valve Closed Position Learning" .
4. Perform EC-78, "
Idle Air Volume Learning" .
>> INSPECTION END
7. CHECK INTERMITTENT INCIDENT
Refer to EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3 EC-407
49Refrigerant pressure sensor terminal 1 EC-631
68Power steering pressure sensor terminal 1 EC-449
90APP sensor terminal 7 EC-461

DTC P0850 PNP SWITCHEC-465
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Revision: November 2009 2006 QX56
DTC P0850 PNP SWITCHPFP:23006
Component DescriptionUBS00HBQ
When the gear position is P or N, park/neutral position (PNP) switch is ON.
TCM detects the position because the continuity of the line (the ON signal) exists.
Then the TCM sends the PNP switch signal to the ECM via combination meter.
CONSULT-II Reference Value in Data Monitor ModeUBS00HBR
Specification data are reference values.
On Board Diagnosis LogicUBS00HBS
DTC Confirmation ProcedureUBS00HBT
CAUTION:
Always drive vehicle at a safe speed.
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-II
1. Turn ignition switch ON.
2. Select “P/N POSI SW ” in “DATA MONITOR ” mode with CON-
SULT-II. Then check the “P/N POSI SW ” signal under the follow-
ing conditions.
If NG, go to EC-468, "
Diagnostic Procedure" .
If OK, go to following step.
3. Select “DATA MONITOR ” mode with CONSULT-II.
4. Start engine and warm it up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive sec- onds.
6. If 1st trip DTC is detected, go to EC-468, "
Diagnostic Procedure" .
MONITOR ITEM CONDITION SPECIFICATION
P/N POSI SW

Ignition switch: ON Selector lever: P or N
ON
Selector lever: Except above OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0850
0850 Park/neutral position
switch The signal of the park/neutral position (PNP)
switch is not changed in the process of engine
starting and driving.

Harness or connectors
[The park/neutral position (PNP) switch
circuit is open or shorted.]

Park/neutral position (PNP) switch

Combination meter

TCM
Position (Selector lever)
Known-good signal
N or P position ON
Except the above position OFF
SEF212Y
ENG SPEEDMore than 1,000 rpm
COOLAN TEMP/S More than 70°C (158 °F)
B/FUEL SCHDL More than 2.0 msec
VHCL SPEED SE More than 64 km/h (40 MPH)
Selector lever Suitable position
SEF213Y

EC-466Revision: November 2009
DTC P0850 PNP SWITCH
2006 QX56
Overall Function CheckUBS00HBU
Use this procedure to check the overall function of the park/neutral position (PNP) switch circuit. During this
check, a 1st trip DTC might not be confirmed.
WITH GST
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 102 (PNP switch signal)and ground under the following conditions.
3. If NG, go to EC-468, "
Diagnostic Procedure" .
Condition (Gear position) Voltage V (Known-good data)
P or N position Approx. 0
Except the above position BATTERY VOLTAGE
(11 - 14V)
MBIB0043E

DTC P0850 PNP SWITCHEC-467
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Revision: November 2009 2006 QX56
Wiring DiagramUBS00HBV
BBWA2105E

EC-468Revision: November 2009
DTC P0850 PNP SWITCH
2006 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureUBS00HBW
1. CHECK DTC WITH TCM
Refer to AT- 3 8 , "
OBD-II Diagnostic Trouble Code (DTC)" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2. CHECK STARTING SYSTEM
Turn ignition switch OFF, then turn it to START.
Does starter motor operate?
Ye s o r N o
Yes >> GO TO 3.
No >> Refer to SC-10, "
STARTING SYSTEM" .
3. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Disconnect combination meter harness connector.
4. Check harness continuity between A/T assembly terminal 9 and combination meter terminal 39. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors F14, E5

Harness connectors E152, M31

Harness for open or short between A/T assembly and combination meter
>> Repair open circuit or short to ground or short to power in harness or connectors.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
102 GR/R PNP switch [Ignition switch: ON]

Selector lever: P or N
Approximately 0V
[Ignition switch: ON]

Except the above gear position BATTERY VOLTAGE
(11 - 14V)
Continuity should exist.

DTC P0850 PNP SWITCHEC-469
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5. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 102 and combination meter terminal 40. Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Harness for open or short between ECM and combination meter
>> Repair open circuit or short to ground or short to power in harness or connectors.
7. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-III
1. Disconnect TCM harness connector.
2. Check harness continuity between TCM terminal 8 and A/T assembly terminal 9. Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK INTERMITTENT INCIDENT
Refer to EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace.
9. REPLACE COMBINATION METER
Refer to DI-5, "
COMBINATION METERS" .
>> INSPECTION END
Continuity should exist.
Continuity should exist.