How to check if a Fuel Pump is drawing too much power: Monitor the electrical current used by the pump. Typically a healthy Fuel Pump pulls between 4 to 10 amps depending on the make and model of your vehicle. The pump will pull a lot of current when it starts to go bad, sometimes more than 15 amps, straining the rest of the vehicle’s electrical system causing fuses to blow, wires to melt or the fuel pump relay to fail.
To measure the current draw you will need a digital multimeter or an ammeter. To measure the amperage the tools are connected to the fuel pump circuit, usually at the fuse box, or the pump itself. A reading of insufficient current draw might mean that the pump is struggling due to excessive internal wear, and a reading of excessive current draw per the shop manual would also indicate that the pump is working harder than it should have to overcome excessive impediments to fuel flow, such as clogged fuel filters or a restriction somewhere in the fuel lines. Auto Repair Source found that fully 30% of Fuel Pump failures come from clogged filters, which cause a pump to work harder and draw more power, eventually leading to a breakdown.
Too much power demand can also manifest as dimming headlights or slower operation of accessories. This occurs because the alternator is unable to provide enough energy to all the systems when the pump consumes more than its fair share. Ford F-150 trucks with a failure of the Fuel Pump resulted in excessive current draw through the circuit, in both 21018 and 2019 cases now of note, resulting in multiple electrical failures and dashboard warning messages.
A failed Fuel Pump may also activate the car’s on-board diagnostics (OBD-II) system to trigger error codes examples of which are P0230 (Fuel Pump Primary Circuit Malfunction). The code is frequently seen when there is too much electrical draw on the circuit. Scotty Kilmer, automotive guru, explains, “An overworked fuel pump not only does a number on your battery and efficiency, it can risk other costly electrical repairs.”
To prevent this issue from happening, the fuel system should be maintained regularly, including a replacement of the fuel filter every 20,000 to 30,000 miles, depending on the manufacturer’s recommendation. If a pump failure occurs after ignoring these signs, it can cost you anywhere from $400 to $600 to replace it.
Determining whether your Fuel Pump is drawing excessive electrical current is governed by amperage monitoring, symptom recognition (electrical strain), and timely diagnostic response. Not only does routine maintenance allow you to avoid overdraw problems, but it can also extend the life of the pump, allowing your vehicle to run with full efficiency.