What causes a fuel pump relay to heat up?

heating fuel pump relay

Every car has a fuel pump that is responsible for pushing gas to the engine. The fuel pump relay, or FPR as it’s often called, is what tells the fuel pump when to turn on and off.

A common question we get from our customers at DIY Auto Service is why does my FPR heat up? In order for a car’s engine to run smoothly, there needs to be a constant flow of gas into it. If the FPR overheats, then you may have an electrical issue with your vehicle.

To learn more about this topic and how you can diagnose problems with your own car just drop by our blog!

What it is and what function does the fuel pump relay have?

The fuel pump relay is the electronic component found on all vehicles with an internal combustion engine. To “relay” means to receive and pass on, which it does when you turn your ignition switch from off to run position.

The voltage supplied by this little device will be transferred onto the fuel pump so that it can keep up its function of running smoothly during start-up time as well as while in operation generally speaking – but only if there are no problems or issues associated with this piece of equipment!

So, what causes a fuel pump relay to heat up?

The relay operates as the current passes through a wire coil winding, creating a magnetic field. The by-product of this is heat. The fuel pump relay is too hot to touch, but this is just normal.

Can the fuel pump relay overheat?

A fuel pump relay has the capacity to overheat and burn up. When this happens, it may melt onto a fuse panel while cutting off power from the ignition system.

Will a car run with a bad fuel pump relay?

If the fuel pump relay has an issue while you are operating it, then power to the fuel pump will be cut off and your engine may stall. A faulty relay might allow a short restart after some time but if completely failed there will not be any chance of starting up again.

Troubleshooting heating fuel pump relay

  • First, locate and pull out the relay and make sure it’s in good shape. There should be no signs of corrosion or overheating on the terminals as well as its socket.
  • Overheating and corrosion can impede proper flow and cause problems. The corrosive substance on the terminals and socket can be cleaned off with an electrical contact cleaner.
  • Check all of the fuses before you begin to do any repair.

How to quickly test a suspicious fuel pump relay

Find a relay that is identical to the one you are suspecting! Remove and replace with a relay with the same configurations as your old one. Check if your car fires up, if it does buy yourself a brand new fuel pump relay. If not, you should seek the problem elsewhere.

6 Bad Fuel Pump Relay Symptoms

If this part is going out, you’re going to know it right away! Your vehicle may be stuttering and halting or have poor acceleration. It could also just die outright when revved up.

If your car hasn’t started in a while (or even at all), then the part might need replacing ASAP before something catastrophic happens like destroying a fuel line that costs thousands of dollars! I suggest getting this done immediately for around $30 – which will save hundreds if not more on repairs later down the road.

1. Check Engine Light(Malfunction Indicator Lamp)

In most cases, the primary symptom is a check engine light. And you know what this means right? It’s a sign that your ECU has some trouble codes in it. In order to read them, you’ll need an OBD2 scan tool and if there are any P0230 or P0231 Diagnostic Trouble Codes (DTC) then chances are good it is faulty wiring on the primary circuit of your fuel pump!

For some reason, your ECU is telling you that the voltage readings from the fuel pump are below what it requires. But this doesn’t mean there’s an issue with the relay! There could be a blown fuse, frayed wiring or a blown circuit which would also cause these issues.

2. Silent fuel pump

What if your fuel pump is broken, but you can’t tell because it’s silent? Now there is a trick to check!

Park near and try turning on the car with your friend standing by. If they hear a clicking or high-pitched hums when turning the key to start position it’s all good.

3. Car shuts down while driving

Another cause of a bad fuel pump relay is car dies while driving! Yes, I know that it’s a very bad position to get into, but it’s a good sign that you have to replace this part!

4. Limited performance of your vehicle

If your car has been showing signs of having a faulty fuel pump, you should be aware that there are some telltale symptoms. These include engine stalling, weak acceleration, bad idling and no-start conditions. But before we get into the details on how to check for a malfunctioning fuel relay system – it is important to know what can cause these problems in the first place!

Some other reasons why cars might have issues with their engines as well as poor performance could also stem from ignition plugs or spark plug wires being an issue within the vehicle’s combustion chamber.

5. Unusual longer starting time of your car

Find yourself cranking the motor over for more than 10 seconds?

Yup, that’s a sign you have fuel issues and should investigate this part as well as your fuel pump. It could even be something small like dirty injectors or an air leak in the line.

6. No part is designed to last forever!

As all other parts on the car, this is no different! It has it’s lifespan and you should consider replacing it.

How long does a fuel pump relay last?

Your car’s fuel pump relay may not last as long as the rest of your vehicle. That said, many owners wait until it starts to show signs of wear before they replace their faulty components and end up with more problems than just a worn-out part!

So if you’re worried about premature damage or want to give yourself some peace of mind in knowing that everything is running smoothly in your engine bay, keep track as 100-200k miles is the usual range of its lifespan!


I bet that you never ever thought that such a little component will have that big of an impact on your car’s engine. However, in that case, let this article be your motivation to inspect and prevent your fuel pump relay from heating and causing additional expenses to your family budget!

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