2008 INFINITI QX56 engine

EC-236
< COMPONENT DIAGNOSIS >[VK56DE]
P0444, P0445 EVAP CANISTER P
URGE VOLUME CONTROL SOLENOID
VALVE
P0444, P0445 EVAP CANISTER PURG E VOLUME CONTROL SOLENOID
VA LV E
DescriptionINFOID:0000000001351588
SYSTEM DESCRIPTION
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM through CAN communication line.
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass pas-
sage in the EVAP canister purge volume control solenoid valve changes to control the flow rate. The EVAP
canister purge volume control solenoid valve repeats ON/O FF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engi ne control. The optimum value stored in the ECM is
determined by considering various engine conditions. When t he engine is operating, the flow rate of fuel vapor
from the EVAP canister is r egulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control solenoid valve uses a ON/
OFF duty to control the flow rate of fuel vapor from the EVAP canis-
ter. The EVAP canister purge volume control solenoid valve is
moved by ON/OFF pulses from the ECM. The longer the ON pulse,
the greater the amount of fuel vapor that will flow through the valve.
On Board Diagnosis LogicINFOID:0000000001351590
Sensor Input signal to ECMECM functionActuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
1
EVAP canister
purge flow controlEVAP canister purge vol-
ume control solenoid valve
Mass air flow sensor
Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery Battery voltage*
1
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
(Mixture ratio fe
edback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
Wheel sensor Vehicle speed*
2
PBIB2057E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0444
0444 EVAP canister purge volume
control solenoid valve circuit
open An excessively low voltage signal is sent
to ECM through the valve • Harness or connectors
(The solenoid valve circuit is open or
shorted.)
• EVAP canister purge volume control so-
lenoid valve
P0445
0445 EVAP canister purge volume
control solenoid valve circuit
shorted An excessively high voltage signal is sent
to ECM through the valve • Harness or connectors
(The solenoid valve circuit is shorted.)
• EVAP canister purge volume control so-
lenoid valve
Revision: March 2010 2008 QX56

P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
EC-237
< COMPONENT DIAGNOSIS > [VK56DE]
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EC
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DTC Confirmation ProcedureINFOID:0000000001351591
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, conf
irm battery voltage is more than 11V at idle.
WITH CONSULT-III
1. Start engine and let it idle for at least 13 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-237, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351593
1.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect EVAP canister purge volume control solenoid valve harness connector.
3. Turn ignition switch ON.
4. Check voltage between EVAP canister purge volume control
solenoid valve terminal 1 and ground with CONSULT-III or
tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E2, F32
• Harness for open or short between EVAP canister purge volume control solenoid valve and IPDM E/R
• Harness for open or short between EVAP canister purge volume control solenoid valve and ECM
>> Repair harness or connectors.
3.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OUTPUT SIGNAL CIRCUIT
FOR OPEN AND SHORT1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 45 and EVAP canister purge volume control solenoid valve terminal 2. Refer to Wiring Diagram.
BBIA0366E
Voltage: Battery voltage
PBIB2245E
Revision: March 2010 2008 QX56

EC-238
< COMPONENT DIAGNOSIS >[VK56DE]
P0444, P0445 EVAP CANISTER P
URGE VOLUME CONTROL SOLENOID
VALVE
4. Also check harness for short to ground and short to power.
OK or NG
OK (With CONSULT-III)>>GO TO 4.
OK (Without CONSULT-III)>>GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE OPERATION
With CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine.
3. Perform “PURG VOL CONT/V” in “ACTIVE TEST” mode with CONSULT-III. Check that engine speed var- ies according to the valve opening.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.CHECK EVAP CANISTER PURGE VO LUME CONTROL SOLENOID VALVE
Refer to EC-238, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace EVAP canister purge volume control solenoid valve.
6.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000001351594
EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
With CONSULT-III
Check air passage continuity of EVAP canister purge volume control
solenoid valve under the following conditions.
Without CONSULT-III
Check air passage continuity of EVAP canister purge volume control
solenoid valve under the following conditions. Continuity should exist.
Condition
(PURG VOL CONT/V value) Air passage continuity
between A and B
100% Yes
0% No
PBIB2058E
ConditionAir passage continuity
between A and B
12V direct current supply between
terminals 1 and 2 Ye s
No supply No
PBIB2059E
Revision: March 2010 2008 QX56

P0447 EVAP CANISTER VENT CONTROL VALVEEC-239
< COMPONENT DIAGNOSIS > [VK56DE]
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P0447 EVAP CANISTER VENT CONTROL VALVE
Component DescriptionINFOID:0000000001351596
The EVAP canister vent control valve is located on the EVAP canis-
ter and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the
canister vent. The ability to seal
the vent is necessary for the on board diagnosis of other evaporative
emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the evapo-
rative emission control system is depressurized and allows EVAP
Control System diagnosis.
On Board Diagnosis LogicINFOID:0000000001351598
DTC Confirmation ProcedureINFOID:0000000001351599
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, conf irm battery voltage is more than 11V at idle.
WITH CONSULT-III
1. Start engine and wait at least 8 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-239, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351601
1.INSPECTION START
Do you have CONSULT-III?
Ye s o r N o
Yes >> GO TO 2.
No >> GO TO 3.
PBIB1263E
BBIA0443E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0447
0447 EVAP canister vent con-
trol valve circuit open An improper voltage signal is sent to ECM
through EVAP canister vent control valve. • Harness or connectors
(The valve circuit is open or shorted.)
• EVAP canister vent control valve
Revision: March 2010 2008 QX56

P0448 EVAP CANISTER VENT CONTROL VALVEEC-243
< COMPONENT DIAGNOSIS > [VK56DE]
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P0448 EVAP CANISTER VENT CONTROL VALVE
Component DescriptionINFOID:0000000001351603
The EVAP canister vent control valve is located on the EVAP canis-
ter and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the
canister vent. The ability to seal
the vent is necessary for the on board diagnosis of other evaporative
emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the evapo-
rative emission control system is depressurized and allows EVAP
Control System diagnosis.
On Board Diagnosis LogicINFOID:0000000001351605
DTC Confirmation ProcedureINFOID:0000000001351606
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 and wait at least 5 seconds.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
4. Start engine and let it idle for at least 1 minute.
5. Repeat next procedures 3 times.
a. Increase the engine speed up to 3,000 to 3,500 rpm and keep it for 2 minutes and 50 seconds to 3 min- utes.
Never exceed 3 minutes.
b. Fully released accelerator pedal and keep engine idle for about 5 seconds.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to EC-244, "
Diagnosis Procedure".
If 1st trip DTC is not detected, go to the next step.
8. Repeat next procedure 20 times.
PBIB1263E
BBIA0443E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0448
0448 EVAP canister vent con-
trol valve close EVAP canister vent control valve remains
closed under specified driving conditions. • EVAP canister vent control valve
• EVAP control system pressure sensor
and the circuit
• Blocked rubber tube to EVAP canister
vent control valve
• EVAP canister is saturated with water
Revision: March 2010 2008 QX56

EC-244
< COMPONENT DIAGNOSIS >[VK56DE]
P0448 EVAP CANISTER VENT CONTROL VALVE
a. Quickly increase the engine speed up to 4,000 to 4,500 rpm or more and keep it for 25 to 30 seconds.
b. Fully released accelerator pedal and keep engine idle for at least 35 seconds.
9. Check 1st trip DTC.
10. If 1st trip DTC is detected, go to
EC-244, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351608
1.CHECK RUBBER TUBE
1. Turn ignition switch OFF.
2. Disconnect rubber tube connected to EV AP canister vent control valve.
3. Check the rubber tube for clogging.
OK or NG
OK >> GO TO 2.
NG >> Clean rubber tube using an air blower.
2.CHECK EVAP CANISTER VENT CONTROL VALVE
Refer to EC-245, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace EVAP canister vent control valve.
3.CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor attached.
2. Check if water will drain from the EVAP canister.
Ye s o r N o
Ye s > > G O T O 4 .
No >> GO TO 6.
PBIB0972E
BBIA0443E
BBIA0351E
Revision: March 2010 2008 QX56

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOREC-247
< COMPONENT DIAGNOSIS > [VK56DE]
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P0451 EVAP CONTROL SYST
EM PRESSURE SENSOR
Component DescriptionINFOID:0000000001351610
The EVAP control system pressure sens or detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
On Board Diagnosis LogicINFOID:0000000001351612
NOTE:
If DTC P0451 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293
.
DTC Confirmation ProcedureINFOID:0000000001351613
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. Start engine and wait at least 40 seconds. NOTE:
Do not depress accelerator pedal even slightly.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-247, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351614
1.CHECK GROUND CONNECTIONS
BBIA0443E
PBIB1207E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0451
0451 EVAP control system pressure
sensor performance ECM detects a sloshing signal from the
EVAP control system pressure sensor • Harness or connectors
• EVAP control system pressure sensor
Revision: March 2010
2008 QX56

EC-250
< COMPONENT DIAGNOSIS >[VK56DE]
P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
P0452 EVAP CONTROL SYSTEM PRESSURE SENSOR
Component DescriptionINFOID:0000000001351616
The EVAP control system pressure sens
or detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
On Board Diagn osis LogicINFOID:0000000001351618
NOTE:
If DTC P0452 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293
.
DTC Confirmation ProcedureINFOID:0000000001351619
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:
Always perform test at a temperature of 5 °C (41 °F) or more.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Select “DATA MONITOR” mode with CONSULT-III.
5. Make sure that “FUEL T/TMP SE” is more than 0 °C (32° F).
6. Start engine and wait at least 20 seconds.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-251, "
Diagnosis Procedure".
BBIA0443E
PBIB1207E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0452
0452 EVAP control system pressure
sensor low input An excessively low voltage from the sen-
sor is sent to ECM. • Harness or connectors
(The sensor circuit is open or shorted.)
• EVAP control system pressure sensor
Revision: March 2010 2008 QX56