1990 Infiniti M30FACTORY OEM SERVICE PROCEDURE

Fuel Control Input Signals

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.

FUEL CONTROL SYSTEM INPUT SIGNALS

Application Model Usage
A/C Clutch Signal (1) Q45
Airflow Meter M30 & Q45
Battery Voltage M30 & Q45
Crank Angle Sensor M30 & Q45
Engine (Coolant) Temperature M30 & Q45
Exhaust Gas Temperature Sensor (2) M30 & Q45
Fuel Temperature Sensor M30
Ignition (START) Switch M30 & Q45
Oxygen Sensor M30 & (3) Q45
Park/Neutral (Inhibitor) Switch (4) M30 & (5) Q45
Power Steering Pressure Switch Q45
Secondary Throttle Sensor Q45
Sub-Crank Angle Sensor Q45
Throttle Position Sensor M30 & Q45
Throttle (Idle) Switch M30 & Q45
Vehicle Speed Sensor M30 & Q45
(1) Signal received from automatic A/C amplifier.
(2) California models only.
(3) 2 sensors are used.
(4) Signal received from transmission control unit.
(5) Signal received from P/N relay.
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:

  • 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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