There are a number of reasons why fuel pump relays can fail, whether due to wear and tear, an electrical problem, or environmental causes. A relay mechanism directs electricity to the fuel pump from an electric circuit. The relay is an important component as it actually stops the power to the pump so that no fuel can be supplied to the engine. They can result in stalling, hard starting or an inability to start the vehicle.
Overheat — One of the primary reasons for Relay failing. What this code means is: the fuel pump relay is located in your car's electrical system which also gets hot when working. When the current flowing through the relay exceeds its carrying ability, or if it is caused by long-term use, the relay will overheat and burn out its internal components. The equipment that is high mileage or heavy duty are prone to such failures. As time goes by the internals of the relay can be degraded over use of excessive heat loosing contact and eventually failure to deliver power at all.
Electrical Wear — Another leading cause of relay failure is electrical wear. The relay contains contacts that open and close to switch the fuel pump power. This movement gradually wears on the contacts with every start of the vehicle. These contacts can corrode and become resistive, losing their ability to carry current efficiently after about 100,000 miles. A typical failure mode of a relay is causing the relay to click on and off rapidly.
Faulty Wiring: A problematic fuel pump wiring may specifically induce the relay malfunction. The fuel system also contain wiring that due to vibration and heat cycles can become loose over time becoming intermittently connected causing voltage fluctuations. This spikes in voltage can put stress on the relay and cause them to fail earlier than expected. According to a study conducted by the National Institute for Automotive Service Excellence (ASE), 15% of relay failures in vehicles are due to wiring issues like faulty ground connections and broken wires.
Fuel pump relay damage due to external factors such as moisture or dirt. The contacts inside the relay can cause short circuits to occur and should be corroded by water intrusion into the electrical system. A car that has been subjected to the usual extreme weather, such as heavy rain or snow, can also get this type of damage. Sealing of the relay and wiring will prevent moisture related failures.
In 2019, a large automaker series of recalls underscored just how much damage bad fuel pump relays could cause and affected tens of thousands of vehicles. These defective relays would cut off the fuel pumps which in turn causes engine stalling and power loss to occur making it imperative for a reliable relay for smooth vehicle performance.
It is imperative that you change your functionally faulty Fuel Pump relay to maintain the fuel delivery of your vehicle, otherwise this situation can lead to major engine problems. Spare parts inspection — Inspecting the relay and electrical system component regularly can help detect early signals of failures to prevent breakdowns as well as expensive repairs.