Check Engine

Fuel system pressure issue can trigger ‘Check Engine’ light

Your car’s “Check Engine” or “Service Engine Soon” light can flash on for more than 1,400 different reasons. The light is part of your vehicle’s on-board diagnostics (OBD) system and can indicate anything from a quick fix like a loose gas cap to a major repair like a catalytic converter. Here’s another example of a problem that can trigger the light…

Trouble code: P0087 Fuel Rail/System Pressure – Too Low

Some vehicles are equipped with a returnless fuel supply, which means that the fuel pump is pulse width modulated and can vary in pump speed to deliver fuel to the rail at a variable rate instead of constantly running the fuel pump and regulating the pressure with a pressure regulator, returning fuel back to the tank.

There is a sensor on the fuel rail that monitors fuel pressure at the rail to determine fuel pressure and vary the pump speed accordingly. The PCM (powertrain control module) or ECM (engine control module) has detected that fuel pressure is below specification for the supply commanded to the fuel pump driver module or fuel pump assembly.

Symptoms of a P0087 DTC may include a misfire because of a lean fuel condition, and the vehicle might run rough or lack power on acceleration.

Possible causes:

  • Weak fuel pump, clogged filter or screen, restricted fuel supply line
  • Faulty fuel pump driver module
  • Faulty fuel pressure sensor

Possible solutions:

  • Test fuel pressure at the fuel rail or line
  • Inspect all fuel lines
  • Check for damaged fuel filter
  • Check for damage to the fuel tank
Posted in Check Engine Light.