Problems starting the car engine Nissan Sunny FB15 generations are often associated with electric fuel delivery. When you turn the ignition key and the engine doesn't catch and you don't hear the usual pumping hum from under the hood, the first suspect is the electrical power circuit.
In most cases, the culprit of the malfunction is a burnt-out fusewhich protects gasoline pump from short circuit. On the FB15 model, this part is in an accessible place, but to find it you need to know exactly the location of the blocks and the markings of the contacts.
Ignoring signs of malfunction can lead to complete failure of the power system, especially in traffic jams or on the highway. Understanding the electrical wiring will help you quickly restore the machine's functionality without a service visit.
Location of fuse boxes on Nissan Sunny FB15
To start diagnostics, you need to find two main blocks with fuse links. On Nissan Sunny FB15 they are located in standard places for the B-class platform: one inside the cabin, the second under the hood. Do not look for them in random places, as the manufacturer clearly regulates access zones.
The main unit, responsible for power consumers, is located in the engine compartment. You need to open the hood and find a black plastic box with the inscription FUSE AND RELAY BOX or just a cover with fuse symbols. It is located closer to the battery or to the wall of the engine compartment (fire shield).
The second unit is located inside the car, usually on the driver's side. On the FB15, this is often a panel hidden under a decorative trim to the left of the steering column. To get to it, you will have to carefully pry off the cover with a screwdriver or a plastic card, being careful not to scratch the plastic.
Marking and rating of the fuel pump fuse
Having determined the location of the blocks, begin searching for a specific element. Block covers often have a diagram printed on them, but this may be erased or difficult to read. You need to look for the designation FUEL PUMP or abbreviation F/P.
On most modifications Nissan Sunny FB15 with HR15DE or HR12DE series engines, the fuel pump fuse is rated 15 Amps or 20 Amps. The color of the fuse-link body is usually blue (for 15A) or yellow (for 20A). Always check the actual value marked on the fuse body.
It is important not to confuse this element with fuses relay fuel pump or ECU (electronic control unit). If you pull out the wrong element, the startup problem will not be solved, and you will waste time. Check the diagram on the inside of the block cover under the hood.
⚠️ Attention: Do not try to replace a blown fuse with a part with a higher rating (for example, put 30A instead of 15A). This will cause the wiring to melt and possibly catch fire the next time there is a short circuit.
Sometimes the integrity of the metal jumper inside the plastic is not visually visible, especially if the body is dark in color. In such cases, it is better to use a multimeter or a test lamp to check the continuity of the circuit. The call will give a 100% guarantee of results.
- HR15DE (1.5 l)
- HR12DE (1.2 l)
- Other
- I don't know
Reasons for frequent fuse-link burnout
If you replace a fuse and it blows again after a few minutes of running the engine or immediately after starting, this is a sign of a serious problem. Simply replacing an element will not help here; you need to look for the root of the problem in the system.
The most common reason is jamming the rotor itself fuel pump. Due to wear of the bearings or debris entering the pump chamber, the motor begins to consume a current exceeding the rated current, which instantly destroys the fuse link. The problem could also be a worn commutator brush.
Another option is a violation of the insulation of the power wires going to the fuel tank. Vibration can cause the wire to rub against the body or other elements and short out to ground. Inspect the wiring harness around the fuel tank and under the vehicle.
Sometimes the culprit is not the pump, but the relay fuel pump. If the relay contacts are welded or a short circuit occurs inside it, the current will flow directly, bypassing the standard protection paths, or create voltage surges. Testing a relay often produces unexpected results.
☑️ Check before replacement
Step-by-step instructions for replacement and diagnostics
The replacement process takes minimal time if you have the right tool at hand. You will need a set of flathead screwdrivers, a multimeter and, preferably, tweezers or a special fuse extractor clamp, which often comes with the unit.
First of all disconnect the battery. This is a mandatory safety requirement to avoid accidental short circuits when manipulating the unit. Remove the negative terminal and set it aside.
Open the block cover under the hood. Find the required fuse according to the diagram. Carefully remove it using tweezers or a clamp and inspect the metal bridge inside. If it is torn or melted, the element is faulty.
Insert a new fuse of the same rating until it clicks. Make sure it fits snugly and doesn't wobble. Reconnect the battery and try to start the engine. If the engine starts, the problem is solved.
What to do if there is no fuse?
If you do not have a spare fuse of the required rating, you can temporarily take an element with a lower load (for example, 10A), which is responsible for non-critical systems (for example, a cigarette lighter or backlight), but only until you purchase a new part. Never install bridges made of foil or wire!
If the engine does not start, but the fuse is intact, the problem may be deeper. Check relay fuel pump. It can be replaced in place of another similar relay (for example, a cooling fan) to check the functionality of the circuit.
Always keep a set of fuses of different ratings in the glove compartment. This will save you on the road if the element responsible for the headlights or the fuel pump burns out.
Diagnosis of a power circuit without a fuse
In cases where the fuse is visually intact, but the pump does not work, it is necessary to check the presence of voltage at the pump connector itself. To do this, you will need a multimeter configured to measure DC voltage (DC 20V).
Remove the rear seat or trunk trim to gain access to the fuel pump door. Disconnect the electrical connector going to the pump. Turn on the ignition (without starting the engine).
Place the multimeter probes on the connector pins. One probe to positive, the other to negative. If the multimeter shows 12 Volt (or about 11-14V depending on the condition of the battery), then the circuit is intact, and the problem is in the pump itself. If there is no voltage, look for a break in the wires or a problem in the control unit.
⚠️ Caution: Be careful when checking the voltage at the pump connector. Gasoline exhaust vapors are highly flammable, so work should be carried out in a well-ventilated place, away from open flames.
Also worth checking mass pump Poor contact on the negative terminal can lead to unstable operation or complete failure. Clean the contact and make sure that the conductor is securely attached to the body.
| Item name | Designation on the diagram | Denomination (A) | Location |
|---|---|---|---|
| Fuel pump fuse | F/P | 15-20 | Block under the hood |
| Fuel pump relay | FUEL PUMP | — | Block under the hood |
| EFI fuse | EFI | 10-15 | Block under the hood |
| Ignition fuse | IGN | 10-15 | Block in the cabin |
| ABS fuse | ABS | 30-40 | Block under the hood |
Remember that fuel system works under high pressure. If you plan to remove the pump itself for repairs, be sure to relieve pressure in the lines. To do this, you can turn off the pump fuse and start the engine until it stalls from lack of fuel.
If replacing the fuse does not solve the problem and there is no voltage to the pump, the cause may be a faulty relay or broken wiring rather than the fuse itself.
Features of operation of Nissan Sunny FB15
Cars Nissan Sunny FB15s are known for their reliability, but the electrical system has its own nuances. A common problem is oxidation of contacts in connectors due to moisture entering through the seals. Inspect connections regularly.
Use only high-quality consumables. Cheap analogue fuses may have an incorrect melting point or poor contact, which will lead to false alarms or, conversely, to overheating. Choose brands recommended by the manufacturer.
Don't ignore extraneous sounds. A low hum or crackling noise coming from under the rear seat may indicate worn pump bearings. Replacing the pump in a timely manner is cheaper than repairing the wiring after a short circuit.
⚠️ Attention: If you smell gasoline in the interior, stop using the vehicle immediately. This may indicate a leak in the fuel tank or lines, which is a fire hazard.
Following a maintenance schedule will help avoid sudden breakdowns. Change the fuel filter on time, as a clogged filter puts increased stress on the pump, which reduces its service life and increases the risk of a blown fuse.
How to check the fuel pump relay?
Take a working relay (for example, from a radiator fan) and insert it into the fuel pump socket. If the pump starts working, then your relay is faulty. This is the fastest way to test without a multimeter.
Common mistakes during self-diagnosis
One of the most common mistakes is replacing a fuse without finding out the reason for its blown. If you just put a new element in and the short remains, it will burn out again and you risk damaging the ECU.
Another mistake is incorrect interpretation of the diagram. In some markets Nissan Sunny sold with different configurations, and the location of the fuses may vary. Always check the documentation specifically for your VIN or year of manufacture.
Don't try to "fix" a blown fuse by soldering a jumper. This is a gross violation of operating rules and a guaranteed path to fire. Replacement only on a new element is allowed.
Regular checking of contacts and the use of high-quality spare parts significantly extends the life of the Nissan Sunny FB15 fuel system.
FAQ: Answers to frequently asked questions
Where exactly is the fuel pump fuse located on the Nissan Sunny FB15?
It is located in the main fuse box under the hood. Look for the designation F/P or FUEL PUMP. This is usually a 15A or 20A fuse.
What should I do if the new fuse immediately blows?
This is a sign of a short circuit in the circuit. Most likely, the fuel pump itself is faulty or the wiring is damaged. Do not install a fuse of a higher rating; look for the cause of the short circuit.
Is it possible to start the engine if the fuse is blown?
No, the engine will not start because the fuel pump will not receive power and will not build up pressure in the system. The fuse must be replaced first.
How to check if the fuel pump is working if the fuse is intact?
Try turning on the ignition and listen for a sound under the rear seat. If the pump does not hum, check for voltage at the pump connector using a multimeter.
Do I need to relieve the pressure before checking?
There is no need to relieve pressure to check the fuse or relay. To remove the pump itself, be sure to relieve pressure by turning off the power and letting the engine stop.