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Home >> Infiniti >> 2001 >> G20 Base, Automatic, RE4F03B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0450: EVAP Control System Pressure Sensor (EVAP-CSPS) >> Procedure
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DTC P0450: EVAP Control System Pressure Sensor (EVAP-CSPS): Procedure

  1. Check EVAP-CSPS hose for blockage or leak. See Figure. 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 terminal No. 1 (Pink/Blue wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short between ECM and EVAP-CSPS. Retest system.
  3. Turn ignition off. Check continuity between engine ground and EVAP-CSPS harness connector terminal No. 3 (Black wire). Also check circuit for short to voltage. See WIRING DIAGRAMS article. Repair circuit as necessary and retest system. If ground circuit is okay, go to next step.
  4. Disconnect ECM harness connector. See Figure. Check continuity of White wire between EVAP-CSPS harness connector terminal No. 2 and ECM harness connector terminal No. 84. See Figure. Also check circuit for short to ground and short to voltage. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
  5. Remove EVAP-CPVCV. See Figure. Using jumper wires, apply battery voltage to EVAP-CPVCV terminals. See Figure. Air should flow between ports "A" and "B". Remove jumper wires. Air should not flow. If operation is as specified, go to next step. If operation is not as specified, replace EVAP-CPVCV and retest system.
  6. Disconnect EVAP-CVCV hose. See Figure. Check hose for blockage. Repair as necessary and retest system. If hose is okay, remove EVAP-CVCV. Check for rust in port "B". See Figure. If rust exists, replace EVAP-CVCV and retest system. If rust does not exist, go to next step.
  7. Using jumper wires, apply battery voltage to EVAP-CVCV terminals. See Figure. 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 step  9. If operation is not as specified, go to next step.
  8. Clean EVAP-CVCV ports with compressed air. Repeat step  7. If EVAP-CVCV still does not operate as specified, replace EVAP-CVCV and retest system. If EVAP-CVCV is okay, go to next step.
    9. 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.
  9. Remove 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. Measure voltage between ground and ECM terminal No. 84 by backprobing. See Figure and Figure . Voltage should be .4-.6 volt. Disconnect vacuum pump. 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 and retest system.
    10. CAUTION: DO NOT disassemble water separator.
  10. Remove water separator and inspect for cracks or blockage. See Figure. 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 and retest system.
  11. 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  13. 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  13.
  12. Inspect EVAP canister for damage. Replace, if necessary. Also check hose between water separator and EVAP canister for blockage or leak. Repair as necessary and retest system. If EVAP canister and hose are okay, go to next step.
  13. Reconnect all harness connectors. Disconnect Gray, 8-pin tail sub-harness connector (connector T-20) located under rear of trunk. Check continuity between engine ground and connector T-20 terminal No. 8. See Figure. Also check circuit for short to voltage. See WIRING DIAGRAMS article. Repair circuit as necessary and retest system. If shield circuit is okay, go to next step.
  14. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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