2000 Infiniti QX4FACTORY OEM SERVICE PROCEDURE

DTC P0450: EVAP Control System Pressure Sensor (EVAP-CSPS): Procedure

  1. Check EVAP-CSPS hose for blockage or leak. See Fig 1. Repair as necessary and retest system. If hose is okay, loosen and retighten engine ground bolts. See Figure. Disconnect EVAP-CSPS harness connector. If water exists in connector, repair or replace connector and retest system. If connector is okay, go to next step.
  2. Turn ignition on. Measure voltage between ground and EVAP-CSPS harness connector Pink/Black wire. If voltage is not about 5 volts, repair open or short in Pink/Black wire. If voltage is about 5 volts, turn ignition off. Check continuity between ground and EVAP-CSPS harness connector Black wire. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire.
  3. Disconnect ECM harness connector. See Figure. Check continuity between EVAP control system pressure sensor harness connector Green/Black wire and ECM harness connector terminal No. 62 (Green/Black wire). See Figure. If continuity exists, go to next step. If continuity does not exist, repair open circuit.
  4. Check EVAP-CPVCV. See DTC P0443: EVAP CANISTER PURGE VOLUME CONTROL VALVE (EVAP-CPVCV) . Replace as necessary and retest system. If EVAP-CPVCV is okay, check EVAP-CVCV. See DTC P0446: EVAP CANISTER VENT CONTROL VALVE (EVAP-CVCV) . Replace as necessary and retest system. If EVAP-CVCV is okay, go to next step.
    5. CAUTION: DO NOT apply more than 5.91 in. Hg of vacuum to EVAP-CSPS.
  5. Remove EVAP-CSPS with harness connector connected. Disconnect hose from EVAP-CSPS. Using a hand vacuum pump, apply vacuum to EVAP-CSPS. Measure voltage between ground and ECM harness connector terminal No. 62 by backprobing with vacuum as specified. See Figure. See EVAP CONTROL SYSTEM PRESSURE SENSOR VOLTAGE  table. Replace EVAP-CSPS, if voltage is not as specified. If voltage is as specified, go to next step.
  6. Check for blockage in water separator and EVAP-CVCV hose. Clean or repair as necessary and retest system. If no blockage is found, check EVAP canister for water. See DTC P0440 OR P1440: EVAP CONTROL SYSTEM . Replace canister as necessary. If canister is okay, go to next step.
  7. Disconnect connector B-43 (Gray, 8-pin connector located near EVAP canister). Check continuity between ground and connector B-43 terminal No. 5. See Fig 2. If continuity exists, go to next step. If continuity does not exist, repair open ground circuit.
  8. No problem is currently indicated. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
EVAP CONTROL SYSTEM PRESSURE SENSOR VOLTAGE

Pressure Volts
Atmospheric Pressure 3.0-3.6
2.76 in. Hg .4-.6
Fig 1: Locating EVAP Control System Pressure Sensor (EVAP-CSPS)
G97F06523Courtesy of NISSAN MOTOR CO., U.S.A.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.