2001 INFINITI QX4 Factory Service Manual

Page 929 of 2395

INFINITI QX4 2001  Factory Service Manual On Board Diagnosis LogicNBEC0644NOTE:
If DTC P0455 is displayed with P1448, perform trouble diagno-
sis for DTC P1448 first. (See EC-573.)
This diagnosis detects a very large leak (fuel filler cap fel

Page 930 of 2395

INFINITI QX4 2001  Factory Service Manual IEVAP purge line rubber tube bent.
IBlocked or bent rubber tube to EVAP control system pressure
sensor
ILoose or disconnected rubber tube
IEVAP canister vent control valve and the circuit
IEVAP canist

Page 931 of 2395

INFINITI QX4 2001  Factory Service Manual SEF565X
DTC Confirmation ProcedureNBEC0646
SEF566X
SEF874X
SEF567X
CAUTION:
Never remove fuel filler cap during the DTC Confirmation Pro-
cedure.
NOTE:
IIf DTC P0455 is displayed with P1448, perform t

Page 932 of 2395

INFINITI QX4 2001  Factory Service Manual 8) Stop vehicle.
9) Select ªMODE 3º with GST.
IIf P0455 is displayed on the screen, go to ªDiagnostic
Procedureº, EC-397.
IIf P0440 or P1440 is displayed on the screen, go to ªDiagnos-
tic Proced

Page 933 of 2395

INFINITI QX4 2001  Factory Service Manual 3 CHECK FUEL FILLER CAP FUNCTION
Check for air releasing sound while opening the fuel filler cap.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 CHECK FUEL TANK VACUUM RELIEF VALVE
1. Wipe clean valve housing.

Page 934 of 2395

INFINITI QX4 2001  Factory Service Manual 6 CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
©GO TO 7.
7 CHECK EVAP CANISTER VENT CONTROL VALVE, O-RING AND CIRCUIT
Refer to ªDTC Confirmation Procedureº,

Page 935 of 2395

INFINITI QX4 2001  Factory Service Manual 9 CHECK FOR EVAP LEAK
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªEVAP SYSTEM CLOSEº of ªWORK SUPPORTº mode with CONSULT-II.
3. Touch ªSTARTº and apply pressure into the EVAP line

Page 936 of 2395

INFINITI QX4 2001  Factory Service Manual 10 CHECK FOR EVAP LEAK
Without CONSULT-II
1. Turn ignition switch ªOFFº.
2. Apply 12 volts DC to EVAP canister vent control valve. The valve will close. (Continue to apply 12 volts until the end of