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.
2001 Infiniti QX4 4WDFACTORY OEM SERVICE PROCEDURE
Fuel Injector Circuits (Altima)
- Start engine. Listen to each fuel injector. If every injector clicks, system is okay. If any injector does not click, go to next step.
- Turn ignition off. Disconnect inoperative injector harness connector. Turn ignition on. Measure voltage between ground and injector harness connector terminal No. 2 (Black/Red wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
- Turn ignition off. Disconnect ECM harness connector. See Figure. Check continuity of specified wire between ECM harness connector and appropriate injector harness connector. See FUEL INJECTOR CIRCUIT IDENTIFICATION (ALTIMA) table. See Figure. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
- Check fuel injector. See FUEL INJECTOR . Replace, if necessary. If injector is okay, no problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
FUEL INJECTOR CIRCUIT IDENTIFICATION (ALTIMA)
| Injector No. | ECM Terminal No. | Wire Color |
|---|---|---|
| 1 | 102 | Red/Black |
| 2 | 107 | Yellow/Black |
| 3 | 104 | Green/Black |
| 4 | 109 | Blue/Black |
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.
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