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.
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HOMESERVICE MANUALSNISSAN-DATSUN2003FRONTIER BASE, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - SYSTEM & COMPONENT TESTINGFUEL SYSTEMFUEL DELIVERYFUEL PUMP CONTROL SYSTEM (SENTRA 2.5L)
2003 Nissan-Datsun Frontier Base, Standard
Fuel Pump Control System (Sentra 2.5L)
2003 Nissan-Datsun Frontier Base, StandardSECTION Fuel Pump Control System (Sentra 2.5L)
- Turn ignition on. Pinch supply fuel hose with fingers. Pulsation should be felt on fuel hose for 5 seconds after ignition is turned on. If pulsation is felt, system is okay. If pulsation is not felt, go to next step.
- Turn ignition off. Disconnect fuel pump relay harness connector. Fuel pump relay is located behind left kick panel. See Fig 1. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (Black/Red wire). If battery voltage does not exist, go to next step. If battery voltage exists, leave harness connector disconnected and go to step 4.
- Check the following: If problem is found, repair as necessary. After repair, retest system.
- Measure voltage between ground and fuel pump relay terminal No. 5 (Black/White wire). If battery voltage does not exist, go to next step. If battery voltage exists, go to step 9.
- Check the following: If problem is found, repair as necessary. After repair, retest system.
- Turn ignition off. Disconnect fuel pump harness connector located behind access cover, under rear seat. Check continuity between ground and fuel pump harness connector terminal No. 3 (Black wire). See Fig 2. Check continuity in Black/Yellow wire between fuel pump harness connector terminal No. 1 and fuel pump relay harness connector terminal No. 3. Continuity should exist at both measurements. Also, check circuits for short to ground or short to voltage. If problem is found, go to next step. If no problem is found, go to step 8.
- Check the following: If problem is found, repair as necessary. After repair, retest system.
- Turn ignition off. Disconnect ECM 116-pin harness connector. For ECM location, see Figure. Check continuity of Black/Pink wire between fuel pump relay harness connector terminal No. 2 and ECM harness connector terminal No. 10 (without NVIS) or No. 29 (with NVIS). See Figure. Also, check circuit for short to ground or short to voltage. If problem is found, go to next step. If no problem is found, go to step 10.
- Check the following:
- Check for poor, loose, corroded or damaged terminal connections at in-line harness connectors B3 and M16. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Check for poor, loose, corroded or damaged terminal connections at in-line harness connectors M58 and F26.
- Check for open or short in circuits between ECM and fuel pump relay.
- Working with fuel pump relay, apply battery voltage and ground to terminals No. 1 and 2. When battery voltage is applied, continuity should exist between terminals No. 3 and 5. When battery voltage is removed, continuity should not exist. Replace relay, if test values are not as specified. If relay tests okay, go to next step.
- Check fuel pump. See FUEL PUMP . If problem is found, replace as necessary. If fuel pump is okay, go to next step.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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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.