When the engine air filter becomes dirty or clogged, it restricts the amount of air that can enter the engine. This can lead to an imbalance in the air-fuel mixture, causing the engine to run "rich," meaning there is too much fuel and not enough air.
A dirty air filter can cause your vehicle to throw a Check Engine code. During this instance, the Check Engine Light of your vehicle will turn on. The light turns on because your vehicle is sensing that its engine isn't receiving enough air.
Causes of P0172 and P0175
The first thing to inspect is the air filter and the entry air flow to ensure all is clear. An exceptional dirty air filter that is very restricted can cause both codes to set. Check the entire PCV system and crankcase for excessive fuel odor or dilution.
Since your engine requires a specific air-to-fuel ratio for combustion in your combustion chamber, any tweaks to this mixture can cause your vehicle to run rich or lean. In the case of a clogged fuel filter, your engine will not get the correct amount of fuel that it needs, causing it to run lean.
A dirty air filter restricts airflow into your air handler, causing the system to work harder than it was designed to. This leads to more wear and tear than necessary — particularly on the air handler fan motor.
Yes! A clogged filter can reduce your heat pump or air conditioner's efficiency so much that your HVAC system blows warm or room temperature air, even when set to “cool.” This can be devastating on a sweltering Nevada summer day, where more heat is the last thing you need.
A faulty oxygen sensor is one of the most common causes of a rich-running engine. The oxygen sensor monitors the amount of oxygen in the exhaust stream. If it senses too much oxygen, it will adjust the fuel mixture to make it richer.
Engine Running Rich Symptoms
Low gas mileage. A strong smell of gasoline, especially when idling. Check engine light warning. Engine performance problems.
Addressing the P0172 error code is crucial because a rich air-fuel mixture can lead to numerous engine performance issues and damage. For example, running rich can cause poor fuel efficiency, increased emissions, and potential damage to the catalytic converter and oxygen sensors.
Faulty sensors: The oxygen sensor, mass airflow sensor, and coolant temperature sensor play vital roles in helping the Engine Control Unit determine the correct fuel amount. If any of these sensors send inaccurate information, it can lead to rich mixtures in the engine.
Here are the different possible reasons why you're getting the engine code P0172: Contaminated engine oil (too long since the last oil change) A leaking fuel injector. Excessive fuel pressure due to restriction along the fuel return line or a faulty fuel pressure regulator.
A compromised airflow sensor may provide inaccurate readings, leading to improper fuel injection and negatively affecting engine performance. Furthermore, a dirty air filter can also affect the mass airflow sensor (MAF), causing it to malfunction and potentially triggering warning lights on your dashboard.
A worn filter, especially the engine air filter, can cause numerous issues, including decreasing the effectiveness of your catalytic converter.
When you leave an AC unit's air filter clogged for too long, you can experience a failure of the entire system. This is because the unit can only work for so long at twice the power before it finally breaks down.
If your vehicle's exhaust has too much gas in it, your check engine light will come on. Your vehicle has an Engine Control Unit (ECU), and many sensors send data to it about your vehicle's exhaust. A rich air/fuel mixture will push excess gas through the exhaust, and the ECU will alert you via the check engine light.
Spark Plugs
Finally, the spark plugs affect your air/fuel mixture, and it can get too rich if they are misfiring.
Although the engine won't work optimally, most cars are drivable with the P0172 code.
Potential solutions can include: Replacing faulty oxygen sensors or other malfunctioning sensors. Cleaning or replacing the mass airflow sensor. Cleaning or replacing clogged fuel injectors.
If there's a leak that allows air to be sucked into the crankcase through any opening other than the predetermined crankcase breather hose, it will cause a lean condition. I recently worked on a vehicle that had a small hole in the back of the right-side valve cover caused by a steel vacuum line that rubbed through.
remove the spark plugs. If the are sooty, it's running rich. If the are very light grey, it's lean. If they are grey with a slight brownish tinge, it's about right.
Check Engine Light Comes On
The CEL warning light will turn on when the engine is not getting an adequate supply of air. If you have noticed other symptoms like lackluster acceleration or reduced fuel economy, then that light could very well be telling you the air filter might be clogged and needs to be changed.
Dirty Air Filters Can Cause Frozen Evaporator Coils, Mold, Mildew, and Bacteria Growth. If your air filter gets too congested during the summer cooling season, it may cause lack of airflow to the evaporator or cooling coils.