Problems with the vehicle and its performance are almost a regular thing. Thankfully, a vehicle has a large number of systems and sensors that are monitoring its work. Symptoms can also point to a certain problem. If you notice increased fuel consumption, a strong fuel smell, and performance issues, hook up the car’s computer to the OBD-II scanner. If you get a P0172 code, you need to know what to do.
A P0172 trouble code indicates that the system is too rich at bank 1. That means that too much fuel is used in the combustion process. Bank 1 shows that the problem is in the driver’s side of the engine. For the car to move it needs fuel, air, and, a spark. The mixture of air and fuel needs to be balanced. If it is not, the electronic control module will detect it. It will put out a P0172 trouble code.
The usual culprit for the code P0172 is the fuel system. The identifying symptoms of this problem are rough idling, low performance, and a drop in fuel economy. But, there are more both to the symptoms and to the underlying problems, than these. Stay with us, and we will cover this topic from beginning to end.
The Science Behind OBD-II and the P0172 OBD2 Code
Origins of OBD-II: A Brief Overview
Throughout history, there have been several attempts to electronically monitor the vehicle and its systems. Several manufacturers, like Volkswagen and Toyota, developed their systems. The problem was that those warning systems weren’t standardized.
In 1996. happened a breakthrough and from then there has been a relatively standardized system of diagnostics. It is called an OBD-II system and now all car manufacturers have to use it. The system moved from the US to Europe in 2004. and in 2006. to Australia and New Zealand.
Some manufacturers have their characteristic error codes. But in the majority, all error codes for the same issues are shared by all manufacturers.
P0172 Code: Its Meaning and Importance in Vehicle Diagnostics
For the engine to work and to move the vehicle, it needs to go through the combustion process. Air and fuel are delivered to the combustion chamber. There, that mix is ignited with the spark created by the ignition spark. The air-fuel mixture ratio is 14.7:1, and it needs to be perfect for the engine to run properly.
The P0172 code implies that there is too much fuel in the air-fuel mixture in the engine bank 1. That state is called a rich condition. That is in contrast to a P0171 error code that shows a lean fuel mixture. It points to a lack of fuel. The P0172 is considered a medium to severe error code. Driving with it in the long run is not good for the engine.
Why Does the P0172 Code Appear: Causes and Symptoms
The P0172 code appears when the ECU detects insufficient fuel in the combustion mix. Several symptoms will point that there is a problem with a too-rich mix condition in your engine:
- Check engine light is on
- Fuel consumption is increased
- Black smoke coming from the exhaust
- The strong smell of fuel from the exhaust
- Decreased engine performance
- Poor acceleration
- Rough engine work when idle
- Cylinder misfire (this is usually followed with the P0300 or other misfire code)
- Residue buildup on the spark plug diodes.
There are several causes for this error code, and they are mostly connected to the fuel system.
- Leaky fuel injectors. Problems with leaks can result in extra fuel ending up in the system
- Worn or damaged spark plugs. If the spark plugs are not igniting consistently, that may leave excess unburned fuel in the engine
- Defective purge valve. It releases fuel vapors from the fuel tank vent lines to the intake manifold. From there it moves to the engine to be burned. If it is not working properly, it can add too much fuel vapor
- Faulty oxygen sensor or the air-fuel ratio sensor. Those sensors measure the exhaust gases and the amount of oxygen in them. If they read these values incorrectly, that can lead to a bad air-to-fuel ratio
- Dirty or worn mass air flow sensor (MAF). Its purpose is to measure how much air is entering the engine. If it is not working properly, that will impact the combustion process
- Clogged air filter. When the air filter is blocked, the engine receives a low amount of air
- Clogged fuel filter. Any obstruction in the fuel delivery can cause issues with the air-to-fuel ratio
- Faulty fuel pump. If the fuel pump is producing too low or high fuel pressure, that can also result in the P0172 error code
- A vacuum leak. A vacuum leak adds air that is unmeasured by the sensors. That will create a disbalance in the combustion mix.
Understanding the Potential Damage from the P0172 Code
Impact of P0172 Code on Your Vehicle’s Performance
The combustion process is essential for the work of an engine. For the combustion to be good, it needs the correct amount of air and fuel to be ignited. If there is a disbalance of air and fuel in the mix it will create issues with the engine performance. Also, a lack, of or inconsistent ignition from the spark plug, will cause misfires and other problems.
It is easy to notice symptoms connected with the P0172 code. The engine will work unevenly, and there will be problems with the acceleration and power. The engine will use more fuel than it should, causing an increase in fuel consumption.
Possible Engine Damage: Long-Term Consequences of Ignoring the P0172 Code
A condition when there is too much fuel in the engine will harm several engine parts. The pistons inside engine cylinders will have problems working. They are moving inside the cylinders due to combustion. If the combustion is off, then they cannot work properly. They will wear out quickly and can cause massive internal engine damage.
Next in line are spark plugs. They need to ignite the mixture of fuel and air. If there is too much fuel that can cause a buildup of soot on the spark plug diodes. Finally, the catalytic converter will suffer if the engine is having problems with misfiring.
All these problems are expensive to resolve. You can try to clean the catalytic converter, but sometimes they are only for the scrap yard. Pistons, cylinders, and other engine parts are expensive to fix and rebuild the engine.
Fuel Economy and Emissions: Environmental Impact of P0172 Code
Adding too much fuel into the combustion will result in a rise in fuel consumption. More fuel leads to increased emissions and a negative impact on the environment. You will pay more for the fuel, and you will release more unhealthy gases into the atmosphere.
Practical Steps to Troubleshoot the P0172 Code
Tools You Need to Diagnose P0172 Code
Thankfully, for this operation y, you will not need a whole mechanic toolbox:
- Some basic hand tools, like ratchets and socket wrenches to remove the spark plugs
- An OBD-II scanner to identify the errors
- Multimeter to test the sensors
- Mass airflow sensor cleaner
Step-by-step Guide: How to Identify the P0172 Code
- Connect the ECU to the OBD-II scan tool. Test the system to see if are there any other error codes besides the P0172. If there is, address them first
- Erase the errors a do a short test drive. Check will and when the error will reappear
- First, remove the MAF sensor. It is located between the air filter and the intake manifold. Clean it with the MAF cleaner
- If you are not sure does it works, test it with a multimeter. Connect the red multimeter line to the harness leading to the computer. Connect the black connector to the ground pin on the sensor. Set the multimeter to 20 volts range. The voltage reading should show around 10 volts. If not, the sensor is bad
- Return the new or the old working sensor and delete the error codes. Do another short test drive and check for error
- If the error is still there, check the spark plugs. If you don’t know when they were last replaced, replace the whole set. Again delete the error and try the vehicle
- Next, test the air-fuel and O2 sensors. Again, you will need a multimeter. In the O2 sensor, you should test the resistance (ohms), and the value should be between 5 and 20 ohms. When testing the air-fuel sensor you need to measure the voltage. The regular output is between 2.9 and 3.3 volts
- Finally, check the fuel injectors with a multimeter. Be sure to test the injectors when they are cold. Set the multimeter to measure resistance. Remove the injector’s electrical connector. Now you can access the terminals of the injector. Connect the multimeter leads to the terminals. The polarity is not important. Every car has its precise values, so check the manufacturer’s manual. But, a universal output value is between 11 and 14 ohms. If the values are off then you found a faulty fuel injector.
Check Out Check Out How to Fix P0175 Engine Code in 2 Minutes:
Beyond DIY: When to Seek Professional Assistance
If nothing from above resolves your issue, you should contact the mechanic. Also, if any of the steps are too advanced for your knowledge, ask the mechanic to do them. Mechanics have experience with these problems and know the best way to diagnose and fix the P0172 issue. Sometimes, spending some money on the mechanic is the best money spent.
FAQs on P0172 Code
What Does Bank 1 Too Rich Mean?
If the Bank 1 is too rich it means that too much fuel is delivered to the combustion chambers in the Bank 1.
What Does It Mean When The Air-To-Fuel Mixture Is Too Rich?
When the air-to-fuel mix is too rich, that means that there is too much fuel in the mix. The ratio should be 14.7:1, and that means that to burn 1 kg of fuel you need 14.7 kg of air. When this imbalance happens, that results in engine performance issues.
How Can I Resolve Error Codes P0175 and P0172?
Both P0172 and P0175 are errors that indicate problems with too much fuel in the combustion chamber. To fix it you need to diagnose the underlying issues. Those are usually broken or dirty MAF sensors or broken spark plugs. This problem can also be caused by a faulty O2 sensor or a vacuum leak.
Any component that measures air and fuel can be the cause of this problem. Also, the fuel delivery system is a common suspect. Those include the fuel pump and the fuel injectors.
Can I Drive My Car with the P0172 Code?
Yes, you can drive the car with a P0172 code, but not for too long. Do not plan any long trips with this error. Try to resolve this issue as fast as possible, to avoid further major issues with the engine.
What Is Bank 1 on an Engine?
Bank 1 indicates the location of the number one cylinder bank. Usually, it is in the driver’s side of the engine.
Need More Help with a P0172 Code?
Driving with a P0172 is not a good idea. It harms your engine and catalytic converter. The longer you drive in this state, the more damage you cause. Diagnosing and fixing the P0172 can be difficult. It demands mechanical and electrical knowledge. We went through the steps, but if you found them overwhelming contact the mechanic.
Depending on the problem, the price to fix it will vary. The cheapest fix is the spark plugs. But, in rare cases when the fuel pump is in jeopardy, you will need to pay up to $1,800. In any case, address this issue and resolve it as soon as possible.
