Modern engines need a specific volume of fuel to run efficiently. A fuel pump relay may be familiar to you. This part is located inside the fuel tank of a car and is in charge of applying pressure to the fuel lines so that gasoline is forced into the combustion engine. A fuel pump could malfunction for several different reasons.
The word “relay” means “to receive and transmit.” The fuel pump relay’s responsibility is to provide the fuel pump with the required voltage when the ignition is turned on. The fuel pump will experience problems if the fuel pump relay is problematic. An automobile with a bad fuel pump relay cannot be driven.
The driver can identify symptoms of a bad or broken fuel pump relay by looking at them. Discover all there is to know about fuel pump relays, including how they function, warning signs that the part is failing, how to diagnose, and many upkeep hints to increase their lifespan.
A Fuel Pump Relay: What Is It?
The combustion engine’s fuel pump relay is a crucial component. The fuel pump relay makes sure that there is never a shortage of fuel for the engine, which needs fuel to operate. Usually, the ignition or the Powertrain Control Module (PCM) is in charge of it.
The fuel pump relay is activated and begins supplying power to the pump when the ignition is turned on. On the other hand, power is turned off when the ignition is turned off.
Where Is the Fuel Pump Relay Located In a Car?
The fuse box in the engine bay of the majority of cars houses the fuel pump relay. It is a lengthy, black box with numerous fuses and relays inside.
Refer to the owner’s manual if you can’t find the fuel pump relay right away. Depending on the model and make of your car, it might be on the firewall, under the hood, or close to the steering column.
The fuel pump relay’s job is to supply the fuel pump with the necessary voltage when the ignition is turned on; the word “relay” implies “to receive and transmit.”. If the fuel pump relay is troublesome, issues will arise with the fuel pump.
What Is the Role of a Fuel Pump Relay In a Car?
The “start cycle” of the combustion engine starts when the ignition key is turned to start the vehicle. When the fuel pump relay is turned on long enough, it provides the necessary current to move the fuel pump. Even though there is little voltage generated, the fuel pump always receives it.
Once the engine is running, the fuel pump relay is shut off. The fuel pump relay is once again engaged when the ignition is turned off, but only long enough to turn the fuel pump off and turn the engine off.
What are the Common Bad Fuel Pump Relay Symptoms In a Car?
One benefit of a failing fuel pump relay is that you will immediately recognize the symptoms. It’s not a silent killer, that’s for sure! Along with other issues, the car will stall, stutter, and accelerate slowly. That’s presuming you can even get the car to start.
1. Engine Does Not Start
The engine failing to start is one of the most typical symptoms of a bad fuel pump relay. Numerous turns of the key produce no response from your car.
Nevertheless, a thorough investigation must be done before drawing any conclusions because the no-start problem can also be brought on by several other malfunctions.
2. The Engine Frequently Stalls
You might encounter a situation where you are about to arrive at a destination and your vehicle abruptly stops. The engine of the vehicle needs a constant supply of fuel to operate. This might be a sign that your fuel filter, fuel tank, or fuel relay is malfunctioning.
It is similar to driving without fuel when the fuel pump relay malfunctions and an unexpected engine shutdown is not unexpected. You must maintain a functioning fuel pump relay by performing routine maintenance and repairing it when necessary to avoid getting into such a situation, even though it may be inconvenient at the time.
3. Frequent Power Losses
A bad fuel pump relay is just one of the many issues with your car that can cause power loss. You will first notice a loss of power if your fuel pump relay malfunctions.
For instance, a car that has a bad fuel pump relay may suddenly stop running while you are driving it. Furthermore, if your car breaks down on the freeway, things become even more difficult.
Consider the possibility of being involved in collisions. Therefore, losing power as a result of a bad fuel pump relay is extremely important, and you should get it fixed as soon as you can.
To prevent encountering these circumstances, you must perform routine maintenance on your fuel pump relay.
The fuel pump usually makes a distinctive sound when you start the automobile to let you know it’s operating. These noises show that the electricity is flowing appropriately and smoothly into the fuel pump. If you don’t hear any of these noises when you start the engine, the problem can be a bad fuel pump relay.
4. A Quiet Fuel Pump
When you start your car, the fuel pump typically makes a certain sound to let you know it’s working. These sounds indicate that electricity is being pumped into the fuel pump correctly and smoothly.
On the other hand, a malfunctioning fuel pump relay may be to blame if you don’t hear these noises when you turn on your engine. While the fuel pump relay may be to blame, there are other possibilities, such as a damaged pump, for why the pump isn’t working.
Again, having the car inspected by a qualified mechanic is the best way to be sure.
5. An Active Check Engine Light (CEL)
A Check Engine Light will alert you if there is a problem with your vehicle (in most cases). An illuminated CEL indicates that the ECU has several stored error codes.
You need to connect the car to an OBD2 scanner to read the code. The primary circuit of the fuel pump is broken, according to codes P0230 or P0231. The Fuel Pump Secondary Circuit Low error code is P0231.
This is the ECU’s way of signaling that the voltage readings from the fuel pump are below the required levels. However, this does not directly point to a relay issue.
Frayed wiring, a blown fuse, a blown circuit, and a shorted fuel pump are additional potential causes of this problem.
The most typical DTC codes for this issue are listed below:
- Code P0230
- Code P0231
- Code P0420
- Code P0627
- Code P0628
6. Car with High Mileage
Although a high mileage is not a surefire indicator of a bad fuel pump relay, as your car ages, it becomes more likely that the fuel pump relay will break down just like any other component.
As a result, in addition to checking the other vehicle parts, you might want to think about performing routine maintenance on the fuel pump relay if your car has high mileage.
7. The Fuel Pump Relay Burning
A burning fuel pump relay is the worst symptom and is brought on by high voltage or current. Thankfully, this is a very unusual occurrence. You must take the vehicle as soon as possible to a qualified professional because you cannot perform this repair yourself.
You might be tempted to handle a lot of the issues with your car on your own if you have some basic mechanic knowledge. If you feel confident enough, go for it. But keep in mind that you might void the parts’ warranties or end up doing more harm to the car than good.
Electrical power surges, dust, and a few other things can also cause the fuel pump relay to fail. The engine reacts badly when the pump relay is compromised by dust and rapid voltage variations.
What are the Reasons for the Failure of the Fuel Pump Relay?
Fuel pumps work continuously with the engine to deliver high pressure to the fuel rails and injectors. The pump operates smoothly and stays cool because it is constantly submerged in fuel. Before refilling the tank, some drivers empty it. This shortens the fuel pump’s lifespan by increasing the amount of heat it is exposed to.
The fuel is drained from the priming chamber when the engine is turned off when the car has very little fuel. Similarly to this, when the engine is started, the pump consumes it and remains unprimed until the fuel is added. If this starts to happen frequently, the pump motor burns out, leading to the fuel pump’s complete failure.
The fuel pump relay can also break down as a result of electrical power surges, dust, and a few other factors. Dust and abrupt voltage changes impair the pump relay’s functionality, causing the engine to respond negatively.
Step-By-Step Guide for Diagnosing a Bad Fuel Pump Relay
Do you think your car has a bad fuel pump relay? Here are a few steps to dispel your uncertainties.
Step 1: Park the Vehicle on Safe, Level Ground
Be sure to engage the parking brake and put the transmission in Park or Neutral. Your car should ideally be parked in a garage; we’ll explain why later.
Step 2: Turn on the Ignition Key But Do Not Start the Vehicle
As you turn the key, pay close attention to any sounds coming from your car. This is why we advise parking the car in a covered garage, which will probably be a lot quieter than a public street. Keep an ear out for any clicking or light buzzing.
However, certain vehicles make it nearly impossible to hear any sounds coming from the fuel pump. Skip this step if that is the case.
Step 3: Raise the Hood to Reveal the Relay
The fuel pump relay is located in the engine compartment of the majority of automobiles. The owner’s manual, the service manual, and the internet are all excellent starting points for finding the relay. Even a fuel pump relay diagram could be discovered while looking for the location.
When the key is still in the “ON” position, try to pay closer attention to the relay to hear the clicking or buzzing noise it makes. At this point, you might convince someone to join you.
Step 4: The Sound You Hear Should Help You Decipher
A healthy vehicle should emit some sounds for you to hear. However, when the hood is raised, a fuel pump relay that is broken makes no sound. You can enlist someone’s assistance. If there is absolutely no sound coming from the vehicle, you should test it.
Step 5: Disconnect the Battery’s Negative Cable
Detach the negative cable from the vehicle’s battery using a socket or set of wrenches. By doing this, all circuits that are connected to the fuel pump and its power source are cut off.
A car engine by Carolla / CC BY-SA 3.0. If the fuel pump relay is broken, fuel cannot be given to the engine, which prevents it from starting. Power loss, trouble starting the engine, an odd noise emanating from the pump, or even a car fire are all signs of a faulty fuel pump relay.
Step 6: Lift the Fuel Pump Relay Out
You must be able to complete it manually. An alternative would be a set of needle-nose plyers.
Step 7: Come In with a Multi-Meter Tool
Change the tool’s resistance setting. The input voltage, ground, battery, and load are the four main pins that the majority of fuel pump relays have. The wiring for the fuel pump is directly connected to the load. Connect the probes of the multimeter to the relay’s load pins and the battery.
To provide the relay with power, you must use a 12V voltage regulator or power supply. The relay ground pin should be connected to the power supply ground.
Step 8: Power Up the Input Voltage Pin
Every time you do this, the multi-metering device ought to beep. Your fuel pump relay is either damaged or burned out if that does not occur.
The following action you should take if you experience any of the aforementioned symptoms is to test your fuel pump relay. Online instructional videos on how to test a fuel pump relay can be found. It ought to simplify the troubleshooting process for you.
How to Use a Multimeter to Test a Fuel Pump Relay?
Using online DIYs, fuel pump relay issues can be quickly identified and resolved. The following procedures can be used to test the fuel pump relay using a multimeter:
- From the fuse box, remove the fuel pump relay.
- To remove any dirt or debris from the fuel pump relay, use a wire brush.
- Test the resistance in your fuel pump relay using a multimeter. By reading the relay’s circuit diagram, you must first determine which prong should be connected to the power.
- Make sure the multimeter is in the ohm setting before using it. If not, you won’t be able to take the proper measurement.
- Using a jumper wire, join the relay to the vehicle’s battery.
- Connect the positive and negative wires to the appropriate relay terminals using the jumper’s other side.
- The relay is still operational if you can hear a ticking noise.
- Connect the multimeter’s two probes to the relay’s prongs using the two probes.
- A perfectly functioning relay should be indicated by the multimeter reading as zero. If the result is greater than zero, the relay is malfunctioning and needs to be replaced by a qualified mechanic.
- From the battery and the pump relay, disconnect the multimeter probes and the jumper.
- If the pump relay is operating flawlessly, put it back in the fuse box. Install a new pump relay if necessary.
A check engine light by Wikiuser100000 / CC BY-SA 3.0. A Check Engine Light will alert you if there is a problem with your vehicle. An illuminated CEL indicates that the ECU has several stored error codes. One of such codes can be one indicating a malfunctioning fuel pump relay.
How Much Does a Bad Fuel Pump Relay Replacement Cost?
A fuel pump relay typically costs between $90 and $150 to replace. This is one of the less expensive components when compared to several other car parts. The part itself only costs $20 to $50, but when labor costs are added in, the price may exceed $300.
Costs for parts and labor can be separated into two categories when estimating vehicle repair costs. The same work is more expensive to complete at a dealership than it is at a small repair shop. The cost of labor varies between businesses and even between states.
Although taking your car to a repair facility is significantly less expensive, some people prefer to have their cars fixed at the manufacturer’s dealerships. Dealerships have trained mechanics with specialized knowledge of those vehicles on staff as well as internal specialists.
Some people prefer to handle vehicle repairs on their own. If you are familiar with a vehicle’s components, DIY may be a financially advantageous choice. If you don’t, the problem will inevitably get worse and the cost will increase. Take the vehicle to a professional instead of making the issues worse by trying to handle them yourself.
It’s not difficult to purchase a fuel pump relay. One is available online and in physical car parts stores, Walmart, eBay, and Amazon.com.
How Many Miles Can a Fuel Pump Relay Clock Before It Starts Failing?
One of a car’s more dependable parts is a fuel pump relay. It is made to be durable just like the rest of your car. However, it is prone to damage and will occasionally need repairs.
Typically, oxidation, wear, rust, and usage over time cause the coil and contact points of the fuel pump relay to become damaged early. A fuel pump relay is typically not checked during maintenance, so keep that in mind. As soon as a problem is discovered, a professional change must be made.
As a result, we are unable to predict a fuel pump relay’s expected lifespan using a fixed time frame. This is largely determined by driving habits, the fuel of choice, and the location of the vehicle.
How Can You Clean a Fuel Pump Relay?
Why spend more money having the fuel pump cleaned at the repair shop when you can do it yourself for free? Make it a part of your routine checkups because it’s a simple task.
Fuel pump debris can easily build up. Furthermore, prolonged exposure to heat reduces its effectiveness. Handling the fuel pump relay requires extreme caution because it is powered by electricity.
Start by removing the relay and using a blower to remove the dirt and dust. Keep blowing for a few minutes over it. Use no water. But the ideal cleaning solution would be a little ethanol. Use the cleaner only after making sure the relay is clear of debris and clean.
To remove any remaining dirt, carefully rub the relay with a thin layer of ethanol. Additionally, this stops the component from getting too much dirt on it. The fuel pump relay should be left somewhere open and airy to dry.
OBD2-Scanner Display by KarleHorn / CC BY 3.0. To retrieve the codes linked to a faulty fuel pump relay, you must connect the automobile to an OBD2 scanner. The fuel pump’s primary circuit is damaged, as indicated by codes P0230 or P0231. Error code P0231 denotes a low fuel pump secondary circuit.
Can a Car Operate When It Has a Bad Fuel Pump Relay?
Depending on how badly the fuel pump relay has been damaged. Your vehicle’s engine loses power and stalls when there is a problem with your fuel pump relay, which cuts off the gasoline flow to the engine.
The car might be able to start eventually if the fuel pump relay failure is only minor. On the other hand, if the gasoline pump relay is destroyed, your automobile won’t start. Can a gasoline pump relay, therefore, operate erratically? Depending on how badly the relay has been damaged.
How Can You Start a Car with a Bad Fuel Pump?
Before attempting to drive the car, we strongly advise having it fixed at the mechanic. The best remedy for a malfunctioning fuel pump is to replace the damaged component. Continued use of a damaged fuel pump harms the engine and may result in more serious issues.
No matter how expert these tricks may seem, starting a car with a broken gasoline pump is only a band-aid fix. The motor burns out because of the bad fuel pump. So without further ado, locate a reliable local mechanic or make an appointment with your dealership. Please don’t dismiss this issue lightly.
However, if the situation is grave, you might need to start your car. to travel to the dealership, as an example. Here are some pointers for starting a car with a malfunctioning gasoline pump:
1. Employ a Fuel Pressure Gauge
You can monitor the fuel system with the help of this incredible diagnostic gadget to make sure the engine is performing at its best. A fuel pressure gauge’s job is to keep track of the fuel pressure to avoid damaging the vehicle’s injectors and fuel pump.
Even mechanics use a fuel pressure gauge when attempting to repair a malfunctioning fuel pump since it is so dependable. Using a gasoline pressure gauge is a dependable method and equipment, but it is still only a short-term fix.
A fuel pressure gauge should be connected to your car’s engine to be used. In addition to starting the car, which would otherwise be dead or stalled every five minutes, it will also indicate whether the engine is failing or not.
2. Apply Little External Pressure
Applying a little external pressure to the car is our final piece of advice on this subject. The main problem with a malfunctioning gasoline pump is that it lowers the essential pressure, that the car needs to operate. The automobile ultimately has performance problems.
Put pressure on the car from the outside. The engine will be able to start and run since the pressure source will help the automobile maintain the required pressure level.
3. Retention of Engine Heat
Inside the car’s engine, heat is a vital component that keeps the thing alive and moving. Your automobile will start whether it has a good or defective fuel pump because a reset occurs when the vehicle cools down. Without the necessary heat and pressure, the fuel pump resets. The vehicle’s operation is immediately hampered by a problem.
The best way to start a car with a broken gasoline pump is therefore to regulate the engine’s temperature. The performance of the car will be more stable, and breakdowns won’t happen as frequently.
It doesn’t make sense to start a car with a bad fuel pump relay just because you can! We discourage it if there isn’t an emergency. Poor gasoline pumps might lead to numerous side issues for your vehicles if they are not fixed. The following are some negative impacts of continuing to use a damaged gasoline pump:
- Power outage
- Lower fuel efficiency
- Sputtering engine
- Frequently failing engines
- The engine overheating
Most automotive professionals advise against driving a vehicle that has a damaged fuel pump. The methods mentioned above can be tried, but there are real risks involved, and those risks are substantial. Repair the fuel pump in your car as soon as possible to avoid more costly and troublesome repairs. You don’t want to short-change the engine’s ability to operate at its best.
Tips for Maintenance of an Effective Fuel Pump Relay
Prevention is preferable to treatment. Similarly to this, it is much simpler and less expensive to prevent fuel pump failure than it is to replace the component after it has broken. Here are a few techniques you can use to lengthen the fuel pump’s lifespan.
- Utilizing reputable, high-quality fuel typically prevents a lot of issues. Try to only purchase fuel from stations with high volume. Why not, if the price doesn’t bother you?
- Invest in high-quality, debris-free fuel.
- Keep the gas tank at least a quarter of the way full, or somewhat full.
- Regularly performed routine maintenance on the fuel system and filters. If necessary, replace or repair.
- Avoid draining the fuel tank. As we previously mentioned, this shortens the service life of the tank by allowing excessive heat to enter it.
- Avoid filling up at a gas station right away after a tanker truck has been filled. The bottom debris is stirred up when a big vehicle like this is being refilled.
A little component attached to your fuel pump is the fuel pump relay. When you start your engine, it causes the fuel pump to start, and when you stop your car, it compels it to stop.
Even though the fuel pump relay is a tough car part that can last as long as your car does, it is susceptible to tearing, wear, and full damage.
Your engine cannot run if the fuel pump relay is malfunctioning because fuel is not supplied. A bad fuel pump relay might show itself in several ways, such as power loss, difficulty starting the engine, an unusual noise coming from the pump, or even a car fire.
Although numerous other problems with your car could cause any of the symptoms above, the fuel pump relay might be to blame.
Whatever the source, if you saw any of the warning signs we listed above, you must have your car checked out and fixed by a qualified technician as soon as you can to avoid developing more sophisticated problems that will cost a lot to fix and may result in total vehicle failure.
If you have the necessary mechanical know-how, you can diagnose and replace the fuel pump relay with ease. As a result, many people find it simple to change their fuel pump relay.
Jim Wicks is the founder of MotorVehicleHQ. With over two decades of experience in the automotive industry and a degree in Automotive Technology, Jim is a certified car expert who has worked in various roles ranging from a mechanic, car dealership manager, to a racing car driver. He has owned more than 20 cars over the past 15 years. Ask him about any vehicle you see on the road and he can tell you the make, model and year. He loves the aesthetics of all things cars, and keeps his vehicles in pristine condition.
In his free time, Jim enjoys getting his hands dirty under the hood of a classic car or taking long drives along the country roads. His favorite car? A 1967 Shelby GT500, a true classic that, according to Jim, “represents the pure essence of American muscle.”