6 Symptoms of a Faulty Fuel Pump Control Module
Engine stalling, poor performance, and other problems may indicate a faulty fuel pump control module. Because this integrated component controls the fuel pump, malfunctions can cause serious problems. In this guide, we’ll cover the most common signs of a faulty fuel pump control module and how much it costs to replace it.
Symptoms of a Faulty Fuel Pump Control Module
A fault in your vehicle’s fuel pump control module is often accompanied by many secondary symptoms, some of which can have a significant impact on your vehicle’s drivability. Recognizing these symptoms can help speed up your diagnosis and repair.
1) Rough Idling
An impending failure of your vehicle’s fuel pump control module is often heralded by the sudden onset of rough or erratic idling. This occurs when the fuel pump control module finds itself unable to request the correct fuel supply for the current operating requirements.
2) Hesitation or Decreased Performance
You may also notice a noticeable hesitation when attempting to accelerate if your vehicle’s fuel pump control module is faulty.
3) Stalling
In severe cases, a defective or inoperable fuel pump control module can cause the vehicle to stall. This can happen if the module itself goes into a low demand state and is no longer able to command sufficient fuel delivery, or if the module goes completely offline. In either case, a stall is highly likely.
4) Start/No Start
In most cases, a fuel pump control module failure will eventually cause a no start condition where the vehicle’s engine will start but will not start.
This usually occurs when the fuel pump control module has completely failed and is no longer able to give the command to operate the fuel pump. This means that there is no fuel in the fuel rail for combustion.
5) Increased Fuel Consumption
Under certain circumstances, your vehicle’s fuel pump control module may fail and not meter as much fuel into the fuel rail at any time. This can result in a significant decrease in fuel consumption and more frequent refueling stops. Additionally, you may also notice a decrease in your vehicle’s emissions performance.
6) Possible Engine Check Light
In many cases, an impending failure of your vehicle’s fuel pump control module will cause the engine check light to come on. This occurs when your vehicle’s ECM has one or more fuel system diagnostic trouble codes stored (e.g. P0087 for low fuel pressure).
However, it’s important to note that this type of failure won’t necessarily cause the check engine light to illuminate, and it depends heavily on the specific make and model of your vehicle.
What does the fuel pump control module do? Your vehicle’s fuel pump control module (also known as the fuel pump driver module) regulates the amount of voltage delivered to the fuel pump itself depending on fuel demand under different conditions and circumstances.
This ensures optimal fuel delivery to the fuel rail, allowing for efficient combustion and ensuring your engine delivers the desired performance. The fuel pump control module receives commands from the vehicle’s ECM/PCM.
The ECM monitors the fuel rail pressure during engine operation and requests increased or decreased fuel pump performance accordingly.
Where is it located?The location of the fuel pump control module on a vehicle often varies greatly from model to model.
- In some vehicles, especially GM vehicles, the fuel pump control module is mounted on the crossmember directly above the spare tire.
- In other vehicles, the fuel pump control module is located under the passenger seat or in the engine bay.
- In recent years, manufacturers have made a concerted effort to move vehicles’ fuel pump control modules to a different location, closer to the corresponding fuel pump.
- In some cases, these modules have been relocated to the fuel tank itself or even integrated into the fuel pump.
What causes a fuel pump module to fail? Fuel pump control modules can fail for a variety of reasons, some of which are more common than others. Typically, fuel pump control modules eventually fail due to the effects of overheating and vibration.
Additionally, water can find its way into the fuel pump control module over time as the shell of the module begins to rust from near-constant exposure to moisture.
