Page 1461 of 3371

EC-270Revision: August 2007
DTC P0420, P0430 THREE WAY CATALYST FUNCTION
2004 QX56
5. CHECK INJECTORS
1. Stop engine and then turn ignition switch ON.
2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42,
44, 63 and ground with CONSULT-II or tester.
Refer to Wiring Diagram for Injectors, EC-596
.
OK or NG
OK >> GO TO 6.
NG >> Perform EC-597, "
Diagnostic Procedure" .
6. CHECK IGNITION SPARK
1. Turn ignition switch OFF.
2. Disconnect ignition coil assembly from rocker cover.
3. Connect a known-good spark plug to the ignition coil assembly.
4. Disconnect all injector harness connectors.
5. Place end of spark plug against a suitable ground and crank engine.
6. Check for spark.
OK or NG
OK >> GO TO 7.
NG >> Check ignition coil with power transistor and their circuit.
Refer to EC-583, "
IGNITION SIGNAL" .
7. CHECK INJECTOR
1. Turn ignition switch OFF.
2. Remove injector assembly.
Refer to EM-29, "
FUEL INJECTOR AND FUEL TUBE" .
Keep fuel hose and all injectors connected to injector gallery.
3. Disconnect all ignition coil harness connectors.
4. Reconnect injector harness connector.
5. Turn ignition switch ON.
Make sure fuel does not drip from injector.
OK or NG
OK (Does not drip.)>>GO TO 8.
NG (Drips.)>>Replace the injector(s) from which fuel is dripping.
8. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Trouble is fixed.>>INSPECTION END
Trouble is not fixed.>>Replace three way catalyst assembly.Battery voltage should exist.
PBIB1527E
SEF 5 75 Q
Page 1476 of 3371

DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
EC-285
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EC
Revision: August 20072004 QX56
DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VA LV E
PFP:14920
DescriptionUBS00H4R
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/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is
determined by considering various engine conditions. When the engine is operating, the flow rate of fuel vapor
from the EVAP canister is regulated 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.
CONSULT-II Reference Value in Data Monitor ModeUBS00H4S
Specification data are reference values.
Sensor Input signal to ECM ECM function Actuator
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
A/F sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
Wheel sensor*
2Vehicle speed
PBIB2057E
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V
Engine: After warming up
Air conditioner switch: OFF
Shift lever: N
No loadIdle
(Accelerator pedal is not depressed
even slightly, after starting engine)0%
2,000 rpm —
Page 1477 of 3371

EC-286Revision: August 2007
DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
2004 QX56
On Board Diagnosis LogicUBS00H4T
DTC Confirmation ProcedureUBS00H4U
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 battery voltage is more than 11V 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 at least 13 seconds.
4. If 1st trip DTC is detected, go to EC-289, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0444
0444EVAP canister purge volume
control solenoid valve circuit
openAn 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
solenoid valve
P0445
0445EVAP canister purge volume
control solenoid valve circuit
shortedAn 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
solenoid valve
SEF 0 58 Y
Page 1479 of 3371

EC-288Revision: August 2007
DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
2004 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
45 L/YEVAP canister purge vol-
ume control solenoid valve[Engine is running]
Idle speed
Accelerator pedal is not depressed even
slightly, after starting engine.BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Engine speed is about 2,000 rpm (More
than 100 seconds after starting engine).11 - 1 4 V
111 W /BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]
For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]
More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 9
120BR
BRPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB0050E
PBIB0051E
Page 1480 of 3371

DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
EC-289
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EC
Revision: August 20072004 QX56
Diagnostic ProcedureUBS00H4W
1. CHECK EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE POWER SUPPLY CIR-
CUIT
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-II 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 CIR-
CUIT FOR OPEN AND SHORT
1. 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.
4. Also check harness for short to ground and short to power.
OK or NG
OK (With CONSULT-II)>>GO TO 4.
OK (Without CONSULT-II)>>GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
BBIA0366E
Voltage: Battery voltage
PBIB2245E
Continuity should exist.
Page 1484 of 3371
DTC P0447 EVAP CANISTER VENT CONTROL VALVE
EC-293
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EC
Revision: August 20072004 QX56
DTC Confirmation ProcedureUBS00H52
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 battery voltage is more than 11V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and wait at least 8 seconds.
4. If 1st trip DTC is detected, go to EC-295, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEF 0 58 Y
Page 1486 of 3371

DTC P0447 EVAP CANISTER VENT CONTROL VALVE
EC-295
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EC
Revision: August 20072004 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 ProcedureUBS00H54
1. INSPECTION START
Do you have CONSULT-II?
Ye s o r N o
Yes >> GO TO 2.
No >> GO TO 3.
2. CHECK EVAP CANISTER VENT CONTROL VALVE CIRCUIT
With CONSULT-II
1. Turn ignition switch OFF and then turn ON.
2. Select “VENT CONTROL/V” in “ACTIVE TEST” mode with CONSULT-II.
3. Touch “ON/OFF” on CONSULT-II screen.
4. Check for operating sound of the valve.
Clicking noise should be heard.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
11 7 L / YEVAP canister vent control
valve[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB1679E
Page 1487 of 3371

EC-296Revision: August 2007
DTC P0447 EVAP CANISTER VENT CONTROL VALVE
2004 QX56
3. CHECK EVAP CANISTER VENT CONTROL VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect EVAP canister vent control valve harness connector.
3. Turn ignition switch ON.
4. Check voltage between EVAP canister vent control valve termi-
nal 1 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors E41, C1
IPDM E/R harness connector E119
Harness for open or short between EVAP canister vent control valve and IPDM E/R
>> Repair harness or connectors.
5. CHECK EVAP CANISTER VENT CONTROL VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND
SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 117 and EVAP canister vent control valve terminal 2.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.Voltage: Battery voltage
BBIA0443E
PBIB0152E
Continuity should exist.