Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1990 Infiniti M30FACTORY OEM SERVICE PROCEDURE
Engine Controls - System/Component Tests
- Introduction
- Computerized Engine Controls
- Engine Sensors & Switches
- Notes
- Airflow Meter Test
- Coolant (Engine) Temperature Sensor Test
- Crankshaft Angle Sensor Test
- Detonation (Knock) Sensor Test
- Exhaust Gas Oxygen Sensor (M30) Test
- Exhaust Gas Oxygen Sensor (Q45) Test
- Exhaust Gas Oxygen Sensor Heater Test
- Exhaust Gas Temperature Sensor (CALIF Models) Test
- Fuel Temperature Sensor Test
- Park/Neutral Relay Input (Q45) Test
- Park/Neutral Input (M30) Test
- Park/Neutral Switch Test
- Power Steering Oil Pressure Switch (Q45) Test
- Start (Ignition Switch) Signal Test
- Sub-Crank Angle Sensor (Q45) Test
- Throttle Position Sensor (TPS) & Idle Switch Test
- Vehicle Speed Sensor (Reed-Type) Test
- Relays & Solenoids
- Solenoids
- Fuel System
- Fuel Control
- Idle Control System
- Ignition System
- Emission Systems & Sub-Systems
- Miscellaneous Controls
- Component Locations
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:
- • 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.
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