how to repair code p0171

How Do I Fix An p0171 Code?

• Step 1: Fix Any Vacuum/Intake Leaks One of the most common sources of a p0171 diagnostic trouble code is the...
• Step 2: Fix Fuel Delivery Issues If an engine cannot receive the desired amount of fuel, it will never obtain the proper...
• Step 3: Fix Upstream Exhaust Leaks Exhaust leaks that are upstream of a vehicle’s O2 sensor can provide that...

Full Answer

What causes trouble code p0171 and p0174?

What causes a P0171 code or P0174 code?

• Mass Airflow Sensor (MAF). ...
• Intake manifold gasket leak • fuel injector O-ring leaks (the key to finding fuel injector O-ring leaks is to compare the fuel trims when cold versus hot because the o-rings ...
• Missing, cracked vacuum hose to MAP sensor
• Faulty MAP sensor

What causes a p0171 code?

| What are the Possible Causes of the P0171 Code?

• Intake air leaks
• Faulty front heated oxygen sensor
• Ignition misfiring
• Faulty fuel injectors
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Faulty Mass Air Flow (MAF) sensor
• Incorrect Positive Crankcase Ventilation (PCV) hose connection

What is the solution to check engine codes p0171?

Check the PCV valve and the EVAP purge valve. You will find a leak or a faulty one-way valve that is causing the P0171 code in most cases. Check the fuel pressure. Connect a fuel pressure gauge to the fuel rail and make sure that the fuel pressure is correct. If it is too low, check the fuel filter, fuel pump, fuel pressure, and regulator.

Is it safe to drive with a code p0171?

While it’s okay to drive your vehicle for a short period of time with the P0171 code showing, you should not wait too long before taking it to the mechanic. For example, only run your car like that until you can get it home and to the mechanic. So, you should never continue to run your car with the P0171 code before having it fixed.

What causes engine code P0171?

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 you fix a lean bank 1?

2:246:28HOW TO FIX SYSTEM TOO LEAN BANK 1 OR BANK 2 ON FORDYouTubeStart of suggested clipEnd of suggested clipAnd that guys could be caused by uh by about five six things guys one could be a bad oxygen sensorMoreAnd that guys could be caused by uh by about five six things guys one could be a bad oxygen sensor oxygen sensor that doesn't send the correct information to the computer.

How much does it cost to fix P0171 code?

You may get lucky with one of the simple repairs mentioned above. A broken vacuum hose sucking in air can be around $50, or a clogged fuel filter for $100. On the other hand, an oxygen sensor or mass air flow sensor can bring a bill of $400 to $500 dollars.

Can a bad fuel pump cause P0171?

A plugged Fuel Filter or poorly functioning Fuel Pump can set the P0171 code. The computer hears (accurately) from the Oxygen Sensor that the Fuel Mixture is too lean so the computer keeps increasing the amount of fuel being delivered into the combustion chambers.

Is it OK to drive with P0171 code?

What Does Code P0171 Mean? Issue Severity: MODERATE– Extended driving with this code can cause internal engine damage. Repair Urgency: Get this code fixed as soon as possible to avoid damage to spark plugs, pistons, and catalytic converters.

Is P0171 serious?

How serious is the P0171 code? The P0171 code is a serious issue. If a vehicle has this code stored in its powertrain control module, the engine of that vehicle simply will not run well. If the engine does not maintain proper air/fuel ratio, there will be a major waste of fuel and a lack of power while driving.

Can a dirty air filter cause a P0171 code?

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 is P0171 system Too Lean bank 1?

The OBDII trouble code P0171 - System Too Lean (Bank 1) means that the engine air-fuel mixture is too lean, or there is too much air and too little fuel. Driving a car with the code P0171 can cause more damage to the engine over time, as when the engine runs lean, the combustion temperature is higher.

How much does it cost to fix a lean engine?

How Can You Solve An Engine Running Lean? Vacuum Leaks – If it's the intake manifold's gaskets, then it'll cost you between $200 to $350. If the entire manifold needs replacing, you could be looking at a cost of around $300 to $700.

How much does it cost to fix code p0174?

How much does it cost to fix P0174?ItemEstimated costOxygen sensor or air-fuel sensor$200-300Cleaning MAF$100Replacing MAF$300Replacing PCV valve$75-1008 more rows•May 10, 2022

Can a bad O2 sensor cause a P0171?

When the ECM/PCM is having to add too much fuel based on input from the O2 sensor, the fault code P0171 will be sent to the ECM, which will trigger the check engine light to illuminate. This code could either mean that the oxygen sensor is detecting too much oxygen or too little fuel in the mixture.

What does the P0171 code mean?

A Code P0171 or system too lean bank 1 means either too much oxygen or too little fuel in the exhaust, which is known as a 'lean' situation or a 'l...

What causes a P0171 code?

Some possible causes of a P0171 engine code are • Vacuum leak • Weak fuel pump • Broken fuel pressure regulator • Blocked fuel filter • Faulty powe...

Is it OK to drive with a P0171 code?

A lean fuel trim code, such as P0171, creates performance issues that might result in costly damage. These issues might range from low fuel economy...

What are the usual symptoms of a P0171 code?

Symptoms of code P0171 include: • Check Engine Light on or flashing • Loss of power • Rough at idle • Misfiring or "coughing" engine • White spark...

How much does it cost to fix code P0171?

When you take your car to a mechanic for diagnosis, most will begin with an hour of labor diagnosing your specific issue. This normally costs betwe...

Will a P0171 code clear itself?

The odds are that it will not. If you notice this code, you should get it checked out as soon as possible.

How do I fix code P0171?

You can usually fix P0171 using the following steps: • Replace the fuel pump or fuel filter • Change the fuel pressure regulator • Replace the powe...

Can a dirty air filter cause a P0171 code?

If your car's air filter becomes blocked or extremely unclean, it will hinder or restrict the flow of air. This, in turn, results in a lean running...

Can bad spark plugs cause P0171?

Quite unlikely. A vacuum leakage downstream from the MAF sensor or a defective MAF sensor are the most common causes of a P0171 (too lean, Bank 1)...

Can a bad PCV valve cause P0171?

Yes, vacuum or intake leaks, low fuel pressure, a defective PCV valve, or a faulty MAF sensor are the most typical reasons for the P0171 code. Howe...

How to fix check engine light code P0171?

Reinstall the mass airflow sensor and clear the check engine light using FIXD. If the check engine light comes back on with code P0171 continue the diagnostic process.

What Does P0171 Mean?

The lean condition can be caused by a vacuum leak, which introduces more air into the air-fuel mixture, or by a weak fuel system, which does not input enough fuel into the air-fuel mixture. To keep the engine running properly, the powertrain control module (PCM) tries to compensate for the lean condition by injecting more fuel to the mixture in an effort to maintain the proper 14.7:1 ratio. When these adjustments become too large, code P0171 is triggered.

How to tell if vacuum is leaking?

Inspect all vacuum lines and hoses for leaks, and make sure they are properly connected. If a leak is present, you will hear a hissing sound, though it may be difficult to hear with the engine running. If you suspect a vacuum leak but are having trouble finding it, check out this detailed guide to finding vacuum leaks.

Can you drive a car with P0171?

It is okay to drive a vehicle with P0171 for a short period of time, but driving with this code for an extended period of time can overheat the engine and cause internal engine damage.

What is the P0171 error code?

Since the P0171 code is a very common error code a driver might face, people make a very common mistake immediately after noticing this error. This mistake is changing the oxygen sensor immediately after seeing issues with the reading.

How to know if you have P0171?

These symptoms usually include: Check engine light illuminating. Engine misfiring.

What to do with P0171?

When dealing with a P0171 code, some suggested DIY's by professional mechanics and automotive experts to help you resolve the problem from home without needing a professional mechanic. The good news here is that these DIYs should work most of the time, which means that you don't have to worry about labor costs.

Why is my P0171 code triggered?

When the P0171 code is triggered due to too little fuel supply. If that's the case, the problem is most likely due to a bad Fuel filter, faulty fuel injector, or malfunctioning fuel pump. Keep in mind that they mentioned causes are the very common primary reasons for a P0171 code. However, there might be additional car parts associated ...

Can P0171 be cleared?

If one of the mentioned DIY's above resolved your issue, do not expect that the P0171 code will clear itself. You must use the OBDII scanner and ask it to clear any inactive error code. Usually, it's also recommended that you scan the system one more time to make sure that their code was removed completely.

What does P0171 mean?

What does code P0171 mean? “Code P0171 – system too lean bank 1” means there is too much oxygen or too little fuel in the exhaust, which is referred to as a “lean” condition, or a lean or “low fuel trim” code. This can be caused by something like a disconnected hose or vacuum leak, which means there’s more air than usual, ...

How serious is a P0171 code?: Is it OK to drive with P0171?

A lean fuel trim code like P0171 causes performance problems that can lead to costly damage, so it’s best to avoid driving with it . These problems can include bad fuel economy, poor engine performance, and even internal engine damage.

How to test for a leak in a car?

How to test for leaks: While the engine is running, spray carburetor or throttle body cleaner around the areas where you think there’s a leak. The engine will either run smoother or rougher and can help you figure out where a leak is located.

What is the code for a bad oxygen sensor?

If an oxygen sensor isn’t sending the correct signal to the computer, that will cause an issue and can trigger a P0171 code.

How to tell if a sprayer is leaking?

Have someone watch the gauges for you while you spray: If the gauges fluctuate, that’s another indicator that should help you find the leak.

How To Diagnose A p0171 Code?

Since there are a number of possible root causes related to the onset of a p0171 fault code, it is important to accurately diagnose the problem at hand before moving forward with any repairs, The following process will assist you in quickly and accurately identifying the source of your trouble.

What Does The p0171 Code Mean?

Fault code p0171 means “system too lean bank 1.” This means that the exhaust gases that are monitored by the first downstream O2 sensor on a given engine bank, are high in oxygen content.

What Caused The p0171 code (Possible Symptoms)?

Any issue, mechanically or electronically, that can cause stifled fuel delivery or unmetered air intake can lead to a lean condition.

What causes a P0171 error?

Some of the most common mechanical causes of a p0171 error code are dirty or clogged fuel injectors, restricted fuel delivery supply or low fuel pressure, leaking vacuum lines or PCV hoses, cracked intake ductwork, and leaking intake gaskets.

What is the most common fault in P0171?

The most common of all p0171 electrical-based faults are dirty or damaged MAF (mass airflow sensors).

What is the purpose of scan tool for P0171?

Prior to performing additional checks, it is important to use a scan tool to check for the presence of any additional codes. Additional codes outside of the predetermined p0171 code can point you in one specific direction over another.

What to do if no other codes are found?

If no other codes are found, the first order of business is to check for vacuum leaks. This can be done in one of two ways. You can either use a vacuum gauge to check for an inability to hold vacuum, or you can use a smoke machine to watch for any damaged intake manifold gasket, lines, or hoses.

How to Diagnose Code p0171?

Since the error code p0171 means the presence of a lean mixture in a vehicle, various sensors may cause the code . In order to diagnose this code, do the following:

What Does Diagnostic Code p0171 Mean?

One thing that you need to know is that there are a number of misconceptions surrounding this error code. There are also some ‘shady’ tips that others give to fix it. My job as a technician is to solve issues like this.

What are the Causes of OBD2 Code p0171?

There are a number of engine parts or sensors which may cause the trigger of the p0171 code, along with a lean mixture. Aside from simply focusing on p0171, it is also best to look for other sensor-related codes. Doing so will be able to provide an indication as to where you can start searching for solutions.

What can you check after a sensor is checked?

After checking all sensor parameters, you can then work on checking all other parts, including intake leaks, fuel pressure, EGR valve, exhaust leaks, MAF/MAP sensor. You can also perform a thorough diagnostics of the sensors, or to check if there are damaged parts inside. For this, you need the help of a diagnostic technician for thorough coverage.

What does p0171 mean?

The diagnostic code p0171 happens when a lean mixture is detected by the front O2 sensors. This lean mixture can either be short term or long term. If the lean mixture is a short term one, it means that the fuel mixture is usually very lean.

What to do if your intake leaks?

Possible Solution: Replace the faulty vacuum hoses, gaskets surrounding the intake, as well as other possible intake leaks.

What to do if fuel pump is not working?

Possible Solution: Replace fuel pump, filter, fuel pressure regulator, or repair the wirings if needed.

What is the code for a lean fuel mixture?

Code P0171 indicates Bank 1 of the engine has a lean fuel mixture. P0174 indicates Bank 2 of the engine has a lean fuel mixture. Engine Bank 1 is the same side of the engine as Engine Cylinder 1. Engine Bank 2 is the opposite side of the engine. A firing order and cylinder location diagram may be needed to see which side ...

Why does my oxygen sensor send two codes?

Depending on the problem, it may send both codes if the issue is causing a lean condition on both engine banks. It’s important to note here, the very nature of the oxygen sensor sending these codes, without any other oxygen sensor fail-codes tells us the sensor is working as it should.

What causes a PCV to leak?

If nothing pops up here, there are other major issues that could be occurring. One is a vacuum leak due to a failed intake manifold or throttle body gasket. This will cause a major vacuum leak and trigger a lean condition.

What is the difference between a bank 1 sensor and a bank 2 sensor?

Your bank 1 or bank 2 sensors will be referred to as “sensor 1” or “sensor 2”. Sensor 1 refers to “upstream” sensors, or the ones near the engine and before the catalytic converter. Sensor 2 is “downstream” or after the converter. These upstream sensors verify the correct air/fuel ratio is entering the engine cylinders by measuring the oxygen levels in the exhaust gases leaving the cylinders. This is done by a continual but changing voltage signal to the computer. A continual high voltage reading indicates a rich fuel mixture, not enough oxygen. A continual low voltage reading indicates a lean fuel mixture, too much oxygen. The optimal ratio is 14.7:1 (air:fuel). When your powertrain/engine control module receives a reading that indicates there’s too much oxygen and the ratio is incorrect, it sends an error code P0171 or P0174. Depending on the problem, it may send both codes if the issue is causing a lean condition on both engine banks. It’s important to note here, the very nature of the oxygen sensor sending these codes, without any other oxygen sensor fail-codes tells us the sensor is working as it should. What makes this code tricky is if this code appears by itself, there is NOT a monitored component that has failed, or it would be getting a code as well. In short, the engine is running lean, but the computer cannot tell why.

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Can you clean MAF sensor?

This is particularly true if you use oiled air filters that have too much oil on them, causing contaminants to cling to your MAF sensor. Once you find your sensor, you can remove it and clean it with MAF cleaning spray, available at AutoZone.