1991 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE

Fuel Control: Notes

Fuel system is controlled by ECU based upon the following sensor input signals. If feedback system does not function properly, check input signals before replacing ECU.

  • A/C Clutch Signal - Signal received from automatic A/C amplifier.
  • Airflow Meter.
  • Battery Voltage.
  • Crank Angle Sensor.
  • Engine (Coolant) Temperature.
  • Exhaust Gas Temperature Sensor (Calif. models only).
  • Ignition (START) Switch.
  • Oxygen Sensor.
  • Park/Neutral (Inhibitor) Switch - Signal received from P/N relay.
  • Power Steering Pressure Switch.
  • Secondary Throttle Sensor (traction control system equipped models only).
  • Sub-Crank Angle Sensor.
  • Throttle Position Sensor.
  • Throttle (Idle) Switch.
  • Vehicle Speed Sensor.
Factory Service Tools

Use the Manual With the Right Hardware

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When to See a Mechanic

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

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

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