Page 445 of 720

DTC P0448 EVAP CANISTER VENT CONTROL VALVE
EC-445
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Revision: 2006 November2007 350Z
DTC Confirmation ProcedureNBS000FP
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 for three 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-447, "
Diagnostic Procedure" .
If 1st trip DTC is not detected, go to the next step.
8. Repeat next procedure for 20 times.
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-447, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
PBIB0972E
Page 447 of 720

DTC P0448 EVAP CANISTER VENT CONTROL VALVE
EC-447
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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 ProcedureNBS000FR
1. CHECK RUBBER TUBE
1. Turn ignition switch OFF.
2. Disconnect rubber tube connected to EVAP 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-449, "
EVAP CANISTER VENT CONTROL VALVE" .
OK or NG
OK >> GO TO 3.
NG >> Replace EVAP canister vent control valve.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
24 BR/YECM 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)
121 LGEVAP canister vent control
valve[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
125 R Power supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB1086E
Page 449 of 720

DTC P0448 EVAP CANISTER VENT CONTROL VALVE
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Revision: 2006 November2007 350Z
Component InspectionNBS000FS
EVAP CANISTER VENT CONTROL VALVE
With CONSULT-III
1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being
rusted.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
3. Reconnect harness connectors disconnected.
4. Turn ignition switch ON.
5. Perform “VENT CONTROL/V” in “ACTIVE TEST” mode.
6. Check air passage continuity and operation delay time.
Make sure new O-ring is installed properly.
Operation takes less than 1 second.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
7. Clean the air passage (Portion A to B ) of EVAP canister vent control valve using an air blower.
8. Perform step 6 again.
Without CONSULT-III
1. Remove EVAP canister vent control valve from EVAP canister.
2. Check portion B of EVAP canister vent control valve for being
rusted.
3. Check air passage continuity and operation delay time under the
following conditions.
Make sure new O-ring is installed properly.
Operation takes less than 1 second.
If NG, replace EVAP canister vent control valve.
If OK, go to next step.
4. Clean the air passage (Portion A to B ) of EVAP canister vent control valve using an air blower.
5. Perform step 3 again.
Condition VENT CONTROL/V Air passage continuity between A and B
ON No
OFF YesPBIB1033E
PBIB1033E
Condition Air passage continuity between A and B
12V direct current supply between
terminals 1 and 2No
OFF Yes
PBIB1034E
Page 450 of 720

EC-450
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
Revision: 2006 November2007 350Z
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSORPFP:22365
Component DescriptionNBS0009B
The EVAP control system pressure sensor detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
CONSULT-III Reference Value in Data Monitor ModeNBS0009C
Specification data are reference values.
On Board Diagnosis LogicNBS0009D
PBIB1086E
PBIB1207E
MONITOR ITEM CONDITION SPECIFICATION
EVAP SYS PRES
Ignition switch: ON Approx. 1.8 - 4.8V
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0451
0451EVAP control system
pressure sensor perfor-
manceECM detects a sloshing signal from the EVAP
control system pressure sensor
Harness or connectors
(EVAP control system pressure sensor
circuit is shorted.)
[CKP sensor (POS) circuit is shorted.]
[CMP sensor (PHASE) (bank 2) circuit is
shorted.]
[EVT control position sensor (bank 2) cir-
cuit is shorted.]
(APP sensor 2 circuit is shorted.)
(Refrigerant pressure sensor circuit is
shorted.)
EVAP control system pressure sensor
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)
(bank 2)
Exhaust valve timing control position
sensor (bank 2)
Accelerator pedal position sensor
Refrigerant pressure sensor
Page 451 of 720
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
EC-451
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Revision: 2006 November2007 350Z
DTC Confirmation ProcedureNBS0009E
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 OFF and wait at least 10 seconds.
2. Start engine and wait at least 40 seconds.
NOTE:
Do not depress accelerator pedal even slightly.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-452, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Page 452 of 720
EC-452
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
Revision: 2006 November2007 350Z
Diagnostic ProcedureNBS0009F
1. CHECK GROUND CONNECTIONS
Models with VDC system, navigation system or telephone
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to EC-150, "
Ground Inspection" .
Models without VDC system, navigation system and telephone
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
1. Body ground E17 2. Body ground E43 3. Body ground B102
:Vehicle front
1. Body ground E17 2. Body ground E43 3. Body ground F152
(Passenger side view with dash side
finisher removed)
:Vehicle front
PBIB3560E
PBIB3561E
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DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
EC-453
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Revision: 2006 November2007 350Z
2. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR CONNECTOR FOR WATER
1. Disconnect EVAP control system pressure sensor harness connector.
2. Check sensor harness connector for water.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace harness connector.
3. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ON.
2. Check voltage between EVAP control system pressure sensor
terminal 3 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 10.
NG >> GO TO 4.
4. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between EVAP control system pressure sensor terminal 3 and ECM terminal
107. Refer to Wiring Diagram.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.
1. Harness connectors T2, B44
2. Harness connectors B1, M12
3. Harness for open between ECM and EVAP control system pressure sensor.
>> Repair open circuit. Water should not exist.
PBIB1086E
Voltage: Approximately 5V
PBIB0138E
Continuity should exist.
Page 455 of 720
DTC P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
EC-455
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Revision: 2006 November2007 350Z
Component InspectionNBS0009G
EVAP CONTROL SYSTEM PRESSURE SENSOR
1. Remove EVAP control system pressure sensor with its harness connector connected from EVAP canister.
Always replace O-ring with a new one.
2. Install a vacuum pump to EVAP control system pressure sensor.
3. Turn ignition switch ON and check output voltage between ECM
terminal 102 and ground under the following conditions.
CAUTION:
Always calibrate the vacuum pump gauge when using it.
Do not apply below -93.3 kPa (-700 mmHg, -27.56 inHg) or
pressure over 101.3 kPa (760 mmHg, 29.92 inHg).
4. If NG, replace EVAP control system pressure sensor.
Applied vacuum kPa
(mmHg, inHg)Voltage V
Not applied 1.8 - 4.8
-26.7 (-200, -7.87) 2.1 to 2.5V lower than above value
PBIB3573E