2001 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE

DTC Confirmation Test (Overall Function Check)

NOTE: Use the following test to check overall function of EVAP purge flow monitoring system. During this test, DTC may not be confirmed.

Malfunction is detected when EVAP system is not functioning properly or there is a leak in hose between EVAP Control System Pressure Sensor (EVAP-CSPS) and intake manifold. Possible causes are:

  • EVAP Canister Purge Volume Control Valve (EVAP-CPVCV) stuck closed.
  • EVAP Canister Purge Control Valve (EVAP-CPCV) stuck closed.
  • Faulty EVAP-CSPS or circuit.
  • Blockage or leak in hoses.
  • Defective EVAP Canister Purge Control Solenoid (EVAP-CPCS).
  • Blockage in MAP/BARO solenoid hose.
  • EVAP canister cracked.
  • Defective EVAP-CPVCV.
  • Defective closed Throttle Position (TP) switch.
  • Check valve between EVAP-CPCS and intake manifold improperly installed.
  • Plugged purge port.
  • Defective EVAP Canister Vent Control Valve (EVAP-CVCV).

To check overall function of purge flow monitoring system, start engine and warm to normal operating temperature. Ensure TCS switch is in OFF position. Turn ignition off and wait at least 5 seconds. Start engine and wait at least 70 seconds. With engine idling, measure and record voltage between ECM terminal No. 92 (EVAP-CSPS signal) and No. 128 (ECM ground) by backprobing. See Figure and Figure . Raise drive wheels and support vehicle. While monitoring voltage, maintain the following conditions for at least one minute:

  • A/C on.
  • Steering wheel turned fully.
  • Headlights on.
  • Engine speed at 3000 RPM.
  • Rear window defogger on.
  • Transmission in any forward gear.

Ensure voltage remains .1 volt less than voltage measured at idle for at least one second.

Factory Service Tools

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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.