If the filter is clogged or excessively dirty, this is enough to impede or restrict the air flow, hence resulting in a lean running condition. Besides a dirty air filter, the P0171 code can also be blamed on a dirty or faulty MAF sensor and a clogged fuel filter.
What codes can a dirty air filter cause?
A contaminated air filter can restrict engine airflow, resulting in a rich air/fuel mixture. This results in incomplete combustion and an engine misfire. A rich fuel mixture can also foul the spark plugs, causing a misfire. An engine misfire can greatly increase vehicle emissions.
How do I fix error P0171 too lean?
What repairs can fix the P0171 code?
- Replacing the fuel pump.
- Replacing the fuel filter.
- Replacing the fuel pressure regulator.
- Replacing the powertrain control module.
- Replacing one or more injectors.
- Replacing one or more oxygen sensors.
- Replacing the mass air flow sensor.
- Repairing a vacuum leak.
Will a dirty air filter cause the check engine light to come on?
A dirty air filter is one of the things that can cause your Check Engine light to come on, caused by an inadequate supply of air to the engine that results in a buildup of carbon deposits. Have your mechanic scan your vehicle to track down the source of the problem, as it could be as simple as replacing the air filter.
Can a dirty MAF cause a P0171?
Problems with the mass air flow (MAF) sensor causing the code P0171 are fairly common in many vehicles. Sometimes the mass air flow sensor just gets dirty and gives false air flow readings causing the engine to run lean.
Will a dirty filter keep AC from working?
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As a result of the buildup, a dirty filter will also cause poor cold airflow in your air conditioning system. That cold air will be trapped inside your air conditioner, causing ice to form on its coils. Once that happens, your air conditioner will freeze up and become inoperable.
What happens when air filter is too dirty?
A dirty air filter restricts the flow of cold air, causing it to build up inside the air conditioner and lower the internal temperature. Given enough time, that buildup of cold air can eventually cause ice to form on the coils. … General Wear and Tear: Air conditioners just last longer if they’re maintained properly.
Can a bad O2 sensor cause a P0171?
You probably know that the answer the questions is — no! A P0171 or P0174 lean code with an O2 sensor reading lean all the time mean — well, several things. The real problem may not be a bad O2 sensor, but possibly be an engine vacuum leak, low fuel pressure or dirty fuel injectors that are causing the engine run lean.
Can a bad gas cap cause a P0171 code?
It doesn’t set a code that is false. A lean code from a vacuum leak, mass air flow failure, pcv valve bad or low fuel pressure is 171.
What causes a po171 code?
A P0171 code indicates the air-fuel ratio entering your engine block is not ideal. Two main issues typically cause this code. There is either too much air or not enough fuel in the lines to create the right ratio. When there’s too much air, you’ll often find a vacuum leak allowing an excess of oxygen into the line.
How do I know if my air filter needs changing?
8 Signs Your Air Filter Needs Replacing
- Reduced Fuel Economy. …
- Misfiring Engine. …
- Unusual Engine Sounds. …
- Check Engine Light Comes On. …
- Air Filter Appears Dirty. …
- Reduced Horsepower. …
- Black, Sooty Smoke or Flames Exiting the Exhaust. …
- Smell of Gasoline when Starting the Car.
How do I know if my air filter is clogged?
So, here’s how you can tell if you have a dirty air filter:
- The mpg drops.
- The acceleration power and torque may decrease.
- The engine idles roughly.
- The check engine light comes on.
- You smell fuel.
- Your engine makes unusual sounds.
- The engine misfires.
- Dark smoke comes from the exhaust.
Can a bad MAF cause a lean condition?
A faulty MAF sensor can cause your vehicle to run too rich or run too lean. You’ll notice if the tailpipes eject black smoke or when the engine runs rough or backfires.