Fuel System Monitor Not Ready: Meaning, Causes, Fixes

If you come across the “Fuel System Monitor Incomplete, do not panic. Rest assured that you are not alone. It is a common problem in the world of automotive. What message does the “Fuel System Monitor Incomplete” pass to you as the vehicle owner? How can you tackle the problem? I will take you through all that in this article. Ready?

Fuel System Monitor Incomplete 

“Fuel System Monitor Incomplete” is one of the terminologies in the OBD (On-board Diagnostic) system. It indicates that your vehicle cannot undergo an emission test. The work of the OBD system is to closely monitor and log the performance of each of your car’s systems. 

The fuel system monitor enables the Power Control Module to determine how well the fuel system controls the fuel mixture inside the combustion chamber. This is necessary to attain the required air/fuel mixture. The fuel system monitor turns on when your car is in a closed loop.

The “Fuel System Monitor Incomplete” appears each time the OBD system detects a change in the fuel system that can increase the emission level. Because of this change, the OBD system cannot finish the emission control check. 

The fuel system monitor is one of the continuous monitors that run all the time, so long all DTCs are cleared and other driving and engine conditions are met. You might fail a smog text with just this continuous monitor’s not-ready condition. The system monitor does not always require you to drive or complete the drive cycle to get it ready. The appearance can give clues to a series of problems inside the system. 

Some Causes of “Fuel System Monitor Not Ready” 

Faulty OBD system

One cause of the “Fuel System Monitor Not Ready” can be the OBD system itself. A faulty OBD system may report the fuel system monitor as “not ready.”

Other components of the OBD may as well be faulty or damaged. This includes the Fuel Tank Sensor and the Oxygen Sensor. They will render the fuel system monitor incomplete and trigger the appearance of “Fuel System Monitor Incomplete.”

Recent car battery disconnection

If you recently disconnected your car’s battery, probably while repairing some parts of your car, or if you replace your car, your monitor will likely not be ready. The repairs or replacement will affect the OBD system memory.

Failed or repaired Fuel System

Another underlying cause of the “Fuel System Monitor Not Ready” may be that you recently repaired the fuel system or it is malfunctioning. If fuel system parts (e.g., the fuel injections and filter) are not functioning correctly, the test cycle will be incomplete. A break in the flow of electricity during replacement may hinder the monitor from getting ready. 

How to Get Your Fuel System Monitor Ready

To pass an emission test, you must get your monitors ready. So clear all other DTC ins. For the fuel system monitor, try the following suggestions;

  • Ascertain the performance of the OBD system itself.
  • You may need to drive your vehicle around to reset the system if you replace or reconnect your battery. Make sure your fuel level is between 35% and 85%. Then turn on your engine and idle for 10 to 12 minutes. After that, drive your car between a speed of 50 and 60 mph to complete a drive cycle.
  • Check and replace damaged parts in your fuel system.
  • Change the oxygen sensor if it is no longer functioning.
  • Check if the fuel pump is not damaged. If you must replace it, do so. In the fuel system, the fuel pump supplies fuel to the engine. But if the fuel pump is not functioning as it should, it can lead to different issues, like the Fuel System Monitor Not being Ready.
  • Ensure your gas cap is in good condition and not loose. Otherwise, you may need to replace it.
  • Clean the fuel injections thoroughly. Check for any blockage, and if it is necessary to change them, do so. 

How to Find out if On Board Diagnostics (OBD) system is ready for Check

You can see for yourself if your car’s OBD system is ready for an emissions check. While some automakers show you the procedure to get this done, you may not be lucky with others. But the process is straightforward if you don’t have a manual, but it doesn’t work for all vehicle models.

Here are maker-specific emissions check procedures for a few car models and makes.

If you own a Honda or Acura model, follow this emission inspection method:

  • Turn on the ignition
  • Allow it for 20 seconds (don’t start the engine)
  • Wait for the check engine light to come up
  • If the check engine light (CEL) blinks five times, then the fuel system monitor (FSM) isn’t ready. If the light goes off, then the system is ready

The fuel system monitor emission checks for Dodge, Chrysler, and Jeep models require the following steps:

  • Switch on the ignition without starting the engine
  • Allow the check engine light to come on after a few seconds, 15 to be exact.
  •  Does the check engine light blink 10 times and then remain on the solid? Your fuel system monitor isn’t ready.
  • If the light doesn’t blink but yet remains on the solid, then your fuel system monitors are ready for emissions inspection.

For owners of Mercury, Lincoln, and Ford, use this technique:

  • Insert your ignition key into the car
  • Switch your car ignition to the “ON” position
  • Allow it to stay for at least 15 seconds (do not start the engine)
  • The fuel system monitor (FSM) is not ready if the CEL flashes eight times.
  • The monitor is ready if the CEL stays on solid

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Final Thoughts 

The Fuel System Monitor Not Ready means that your car cannot carry out the emission system tests for some reason. And when your vehicle is not ready for an emission check, you may be in for a fix. You may want to ask if you can pass a smog check if my fuel system monitor is incomplete. Depending on your car’s make and model, you may fail an emission test if your fuel system monitor is not ready.

Until you get your monitor ready and clear other DTCs, you will not pass a smog test. So, for the smooth running of your car, follow the suggestions in this article or take your car to a competent mechanic for proper diagnosis and repair.

  • James Smith

    I'm James Smith, a car enthusiast and a content writer for Daily Car Tips. I have a passion for all things cars, from classic muscle cars to the latest electric vehicles. When I'm not writing about cars, you can usually find me tinkering with my car or checking out the latest automotive trends.

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