Error Code P0087 is defined as Fuel Rail/System Pressure Too Low. This indicates a fuel system problem, which is usually a fault within the fuel delivery system.
This error code is very similar to Error Code P0088.
For some vehicles that uses return-less fuel supply, this means their fuel pump is pulse width modulated. Also, its pump speed can vary to deliver rail at variable rate, rather than constantly running the fuel pump and regulating the pressure through pressure regulator, returning fuel back to the tank.
The fuel rail comes with a sensor that monitors its fuel pressure and change the pump speed accordingly. Error Code P0087 is triggered when the PCM (Powertrain Control Module) has detected low fuel pressure (or below the specification commanded to the fuel pump driver module or fuel pump assembly) in its fuel pressure sensor. A problem usually caused by the fuel pump, fuel supply pipe blockage, fuel pressure regulator or mechanical fault.
Low fuel pressure is actually what causes the PCM to activate the Check Engine light. When this happens, a failsafe mode is activated to prevent damages until the problem is fixed/repaired.
Aside from the activation of the Check Engine light, drivers will also experience drivability issues, such as:
- Rough running
- Poor acceleration
- Poor fuel economy
- Engine misfire
- Loss of engine power
Depending on the severity of the problem or the make and model of the vehicle, the engine may experience hard starting or may simply just stop running.
The most common cause of this error code is clogged filter or fuel screen. Other Potential causes include:
- Failed fuel pump
- Restricted fuel line
- High mileage vehicles or bad fuel
- Faulty fuel pressure sensor
- Faulty fuel pump driver module
- Weak fuel pump
- Restricted fuel pump supply line
- Collapsed or kinked fuel line problems restricting fuel flow to high pressure (for GM vehicles 2001 to 2004.
- Failed high-pressure fuel pump camp which leads to low fuel pressure (for Volkswagen 2005-2007.
How to Check
Fuel pressure monitor don’t usually run unless the fuel pressure sensor monitor runs first and passed. Many times, this error code is accompanied with other error code, such as O2 (oxygen) sensor lean or rich code. If this happens, you will need to diagnose and repair it first before you can turn your attention to the fuel pressure itself.
- Start your diagnosis by making sure you didn’t run out of fuel. It is important to have the right amount of fuel to pressurize the lines. In some cases, simply adding a fresh tank of fuel will fix the problem.
- Check for any leaks of fuel. Obvious leaks where you can see fuel dripping, or smell raw fuel, won’t allow the proper buildup of fuel pressure, which will lead to low pressure condition. Repair as needed.
- Inspect the fuel lines for kinks that may obstruct the flow of fuel and prevent the required pressurization. Some plastic fuel lines are more prone to kinking, which will lead it to collapse and obstruct the fuel flow to the high pressure pump (from low pressure pump).
- Make sure the fuel filter is NOT contaminated, especially on high-mileage vehicles. This issue can also obstruct the flow of fuel.
- Check the fuel tank for signs of damage. External fuel tank are prone to damage as they’re exposed to elements, which could impact the fuel sender inside the tank and lead to poor fuel intake of the low-pressure fuel pump.
From here on, you may also want to perform further diagnosis for the high pressure fuel system using special tools and steps.
How to Fix
The diagnosis above can offer quick fix for this error code. The most common fix for this error code however, is to replace the fuel filter or screen. Other quick fixes include:
- For kinked fuel lines, you definitely need to replace them.
- Remove and replace fuel pump.
- Replace faulty fuel pressure sensor.
Error code P0087 is a serious condition, as it can lead to variety of drivability problems. If the engine is misfiring or running poorly, then it must be diagnosed as soon as possible to ensure safe driving and reduce the risk of further damage.
A failed fuel pump can cause the engine to die while driving, which may result to serious problems for the driver.
Make sure you hire a qualified mechanics for a more thorough diagnosis and professional repairs.