LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2001 >> I30 Base, RE4F04B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0450: EVAP Control System Pressure Sensor (EVAP-CSPS) >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

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

  1. Check EVAP-CSPS hose for blockage or poor connection. See Figure. Clean or repair as necessary and retest system. If hose is okay, turn ignition off. Loosen and retighten 2 engine ground bolts located near oil filler cap. Disconnect EVAP-CSPS harness connector. Inspect connector for water. If water exists, repair or replace connector as necessary 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 (Red wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short in Red wire and 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. 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 Canister Purge Volume Control Valve (EVAP-CPVCV). See Figure. Using jumper wires, apply battery voltage between EVAP-CPVCV terminals. See Figure. Check for airflow between ports "A" and "B". Air should flow. 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. Remove EVAP Canister Vent Control Valve (EVAP-CVCV) hose. Check EVAP-CVCV hose for blockage. Clean hose with compressed air, if necessary. If hose is okay, remove EVAP-CVCV. Inspect port "B" for rust. See Figure. Is rust exists, replace EVAP-CVCV and retest system. If rust does not exist, go to next step.
  7. Using jumper wires, apply battery voltage between EVAP-CVCV terminals. See Figure. Air should flow between ports "A" and "B". Disconnect jumper wires. Air should not flow between ports "A" and "B". EVAP-CVCV should switch in one second or less. If EVAP-CVCV operates as specified, go to step  9. If EVAP-CVCV does not operate as specified, go to next step.
  8. Clean EVAP-CVCV ports with compressed air and repeat step  7. If EVAP-CVCV is okay, go to next step. If EVAP-CVCV still does not operate as specified, replace EVAP-CVCV and retest system.
    9. CAUTION: DO NOT apply more than 5.91 in. Hg of vacuum to EVAP-CSPS. DO NOT use ECM ground terminals when measuring voltage. Replace EVAP-CSPS if it has been dropped from a height of more than 20" (.5 m) onto a hard surface such as concrete.
  9. Reconnect all harness connectors. Remove EVAP-CSPS with its harness connector connected. Turn ignition on. Using a suitable hand vacuum pump, apply 2.76 in. Hg 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. Check for blockage in hose to EVAP-CVCV. Clean, if necessary and retest system. If hose is okay, remove water separator. See Figure. Visually inspect water separator for blockage or cracks. Inspect hoses for cracks. Repair as necessary and retest system. If no problems are found, go to next step.
    11. CAUTION: DO NOT disassemble water separator.
  11. 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.
  12. Remove EVAP canister with EVAP-CVCV attached. Invert EVAP canister and attempt to drain water from EVAP canister. If water does not drain from EVAP canister, go to step  14. If water drains from EVAP canister, go to next step.
  13. Weigh EVAP canister with EVAP-CVCV attached. If EVAP canister weighs less than 4.0 lbs. (1.8 kg), go to next step. If EVAP canister weighs 4.0 lbs. (1.8 kg) or more, inspect EVAP canister for damage and hoses to water separator for poor connections or blockage. Repair as necessary and retest system.
  14. On Maxima, go to next step. On I30, reconnect all harness connectors. Disconnect connector M-2 (Brown, 24-pin connector located behind left side of instrument panel, below fuse block). Check continuity between ground and connector M-2 terminal No. 10. See Fig 1. See SYSTEM WIRING DIAGRAMS article. Also check circuit for short to voltage. Repair as necessary and retest system. If shield circuit is okay, go to next step.
  15. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Identifying Connector M-2 Terminals (I30)
G99F54812Courtesy of NISSAN MOTOR CO., U.S.A.
scientia non olet · About LEMON Manuals