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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 68 (Engine Controls Self-Diagnostics - Pathfinder & QX4) >> Diagnostic Tests >> DTC P1446: EVAP Canister Vent Control Valve - Stuck Closed >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Pathfinder and 2002 Infiniti QX4. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Disconnect vacuum hose from EVAP-CVCV. See Figure . Check hose for blockage. If blockage exists, clean hose with compressed air. If blockage does not exist, go to next step.
    2. CAUTION: DO NOT disassemble water separator.
  2. Remove water separator and inspect for cracks or blockage. With water separator port "A" plugged, blow air into port "B". See Figure . Air should flow out of port "C". With port "C" plugged, blow air into port "B". Air should flow out of port "A". If operation is as specified, go to next step. If operation is not as specified, replace water separator. After repair, repeat DTC CONFIRMATION TEST  .
  3. Remove EVAP-CVCV from EVAP canister. Check for rust in port "B". See Figure . If rust does not exist, go to next step. If rust exists, replace EVAP-CVCV. After repair, repeat DTC CONFIRMATION TEST  .
  4. If using CONSULT-II, go to next step. If using generic scan tool, go to step  6 .
  5. Reconnect all harness connectors. Turn ignition on. Perform VENT CONTROL/V in ACTIVE TEST mode with CONSULT-II. When VENT CONTROL/V is ON, air should not flow between ports "A" and "B". When VENT CONTROL/V is OFF, air should flow between ports "A" and "B". It should take less than one second for valve to open or close. If operation is as specified, go to step  7 . If operation is not as specified, clean EVAP-CVCV with compressed air, and retest. If operation is still not as specified, replace EVAP-CVCV. After repair, repeat DTC CONFIRMATION TEST  .
  6. Using jumper wires, apply battery voltage to EVAP-CVCV terminals. With voltage applied, air should not flow between ports "A" and "B". Remove jumper wires. Air should flow. EVAP-CVCV should switch in less than one second. If operation is as specified, go to next step. If operation is not as specified, clean EVAP-CVCV with compressed air, and retest. If operation is still not as specified, replace EVAP-CVCV. After repair, repeat DTC CONFIRMATION TEST  .
  7. Remove EVAP canister with EVAP-CVCV attached. Attempt to drain water from EVAP canister. If water does not drain from EVAP canister, go to step  10 . If water drains from EVAP canister, weigh EVAP canister with EVAP-CVCV attached. If weight is more than 4.0 lbs. (1.8 kg), go to next step. If weight is less than 4.0 lbs. (1.8 kg), go to step  9 .
  8. Inspect EVAP canister for damage. If problem is found, replace as necessary. Also check hose between water separator and EVAP canister for blockage or leak. If a problem is found, repair hose or replace EVAP canister as necessary. If no problem is found, go to next step. After repair, repeat DTC CONFIRMATION TEST  .
  9. Check for disconnection or improper connection of hose connected to EVAP-CSPS. If a problem is found, repair as necessary. If no problem is found, disconnect EVAP-CSPS 2-pin harness connector. Check for water damage to connector and terminals. If water damage does not exist, go to next step. If water damage exists, replace EVAP-CSPS. After repair, repeat DTC CONFIRMATION TEST  .
    10. CAUTION: DO NOT apply more than 5.91 in. Hg (20 kPa) of vacuum to EVAP-CSPS. Replace EVAP-CSPS if it has been dropped from a height of more than 20" (.5 m) onto a hard surface such as concrete.
    CAUTION: DO NOT use ECM ground terminals when measuring voltage.
  10. Remove EVAP Control System Pressure Sensor (EVAP-CSPS) with its harness connector connected. See Figure . Turn ignition on. Using a hand vacuum pump, apply 2.76 in. Hg (9.3 kPa) of vacuum to EVAP-CSPS. Backprobbing at ECM, measure voltage between ground and ECM terminal No. 84 (Blue/Green wire). See Figure and Figure . With 2.76 in. Hg (9.3 kPa) of vacuum applied to EVAP-CSPS, voltage should be .4-.6 volt. When vacuum is removed, voltage should be 3.0-3.6 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace EVAP-CSPS. After repair, repeat DTC CONFIRMATION TEST  .
  11. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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