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Home >> Nissan-Datsun Truck >> 2002 >> Xterra XE 2WD V6-3.3L (VG33E) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P1456

P1456

P1456 EVAP CONTROL SYSTEM




On Board Diagnosis Logic
This diagnosis detects very small leaks in the EVAP line between the fuel tank and the EVAP canister purge volume control solenoid valve using intake manifold vacuum (negative pressure when P0456) or fuel tank vapor pressure (positive pressure when P1456) in the same way as conventional EVAP small leak diagnosis. If the ECM judges a leak equivalent to a very small leak, the very small leak DTC P0456 or P1456 will be detected. If the ECM judges a leak equivalent to a small leak, the EVAP small leak DTC P0442 or P1442 will be detected. Correspondingly, if the ECM judges there is no leak, the diagnosis result is OK.

Malfunction is detected when EVAP control system has a very small leak, EVAP control system does not operate properly.

CAUTION:
- Use only a genuine NISSAN fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may come on.
- If the fuel filler cap is not tightened properly, the MIL may come on.
- Use only a genuine NISSAN rubber tube as a replacement.

POSSIBLE CAUSE
- Incorrect fuel tank vacuum relief valve
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close.
- Foreign matter caught in fuel filler cap.
- Leak is in line between intake manifold and EVAP canister purge volume control solenoid valve.
- Foreign matter caught in EVAP canister vent control valve.
- EVAP canister or fuel tank leaks
- EVAP purge line (pipe and rubber tube) leaks
- EVAP purge line rubber tube bent.
- Blocked or bent rubber tube to EVAP control system pressure sensor
- Loose or disconnected rubber tube
- EVAP canister vent control valve and the circuit
- EVAP canister purge volume control solenoid valve
- Fuel tank temperature sensor
- O-ring of EVAP canister vent control valve is missing or damaged.
- Water separator
- EVAP canister is saturated with water.
- Fuel level sensor and the circuit
- EVAP control system pressure sensor
- Refueling control valve
- ORVR system leaks

DTC Confirmation Procedure

CAUTION: Never remove fuel filler cap during the DTC confirmation procedure.

NOTE:
- If DTC P0456 or P1456 is displayed with P0442, perform TROUBLE DIAGNOSIS FOR DTC P0456 or P1456 first.
- If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
- After repair, make sure that the hoses and clips are installed properly.

TESTING CONDITION:
- Open engine hood before conducting following procedure.
- If any of following condition is met just before the DTC confirmation procedure, leave the vehicle for more than 1 hour.

a. Fuel filler cap is removed.
b. Refilled or drained the fuel.
c. EVAP component parts is/are removed.

- Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

With CONSULT-II
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT-II.
2. Make sure the following conditions are met.

FUEL LEVEL SE: 1.08 - 0.2 V
COOLAN TEMP/S: 0 - 32 °C (32 - 90 °F)
FUEL T/TMP SE: 0 - 35 °C (32 - 95 °F)
INT A/TEMP SE: More than 0 °C (32 °F)

If NG, turn ignition switch "OFF" and leave the vehicle in a cool place (soak the vehicle) or refilling/draining fuel until the output voltage condition of the "FUEL LEVEL SE" meets within the range above and leave the vehicle for more than 1 hour. Then start from step 1).

3. Turn ignition switch "OFF" and wait at least 5 seconds.
4. Turn ignition switch "ON".










5. Select "EVAP VERY/SML LEAK P0456 or P1456" of "EVAPORATIVE SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT-II.

Follow the instruction displayed.

6. Make sure that "OK" is displayed.

If "NG" is displayed, refer to "Diagnostic Procedure" below.

NOTE:
- If the engine speed cannot be maintained within the range displayed on CONSULT-II screen, go to "Basic inspection".
- Make sure that EVAP hoses are connected to EVAP canister purge volume control solenoid valve properly.




Overall Function Check

With GST
Use this procedure to check the overall function of the EVAP very small leak function. During this check, a 1st trip DTC might not be confirmed.

CAUTION:
- Never use compressed air, doing so may damage the EVAP system.
- Do not start engine.
- Do not exceeded 4.12 kPa (0.042 kg/sq.cm, 0.6 psi).

1. Attach the EVAP service port adapter securely to the EVAP service port.
2. Set the pressure pump and a hose.
3. Also set a vacuum gauge via 3-way connector and a hose.
4. Turn ignition switch "ON".
5. Connect GST and select mode 8.
6. Using mode 8 control the EVAP canister vent control valve (close) and vacuum cut valve bypass valve (open).
7. Apply pressure and make sure the following conditions are satisfied.

Pressure to be applied: 2.7 kPa (20 mmHg, 0.79 inHg) Time to be waited after the pressure drawn in to the EVAP system and the pressure to be dropped: 60 seconds and the pressure should not be dropped more than 0.4 kPa (3 mmHg, 0.12 inHg)

If NG, go to diagnostic procedure.

NOTE: For more information, refer to GST instruction manual.

Diagnostic Procedure

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