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.
Engine Control Module (ECM)
The ECM consists of a microcomputer, inspection lights (except Quest), diagnostic mode selector, connectors and wiring for voltage signal input, voltage signal output, and power supply. The unit is not serviceable and should not be opened. Inspection lights are provided on side of unit for self-diagnostic checks. The ECM contains memory and logic circuits, enabling it to interpret sensor inputs and control various engine systems. To locate ECM, see ECM LOCATIONS table.
| Application | Location |
|---|---|
| Altima | Under Center Console |
| Maxima, NX & Sentra | Behind Center Console |
| Pathfinder & Pickup | Under Passenger Seat |
| Quest | Behind Center Instrument Panel |
| 240SX | Behind Passenger-Side Kick Panel |
| 300ZX | Behind Glove Box |
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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