P0151 Ford F150 – Definition, Causes, and Symptoms!

P0151 Ford F150 – Definition, Causes, and Symptoms!

January 4, 2023 0 By CarGuy

Have you experienced the check engine light and diagnosed a P0151 Ford F150? Well, if that is the case, then you are at the right place because in this article, there will be quite a lot to cover and we will try to help you solve your problem.

Doing your own research should be one of your top priorities. Out there are a ton of fishy mechanics who want to rip you off by replacing a ton of components on your car until they finally solve the problem. And if you are not self-aware, this could cost you thousands of dollars.

So, proper research is needed by your side in order for you to determine more about the problem and what could be causing it. But you shouldn’t worry because we are here to help you out when it comes to solving this problem on your F-150 truck.

First, we are going to introduce ourselves to car diagnostics and learn more about the basics of how proper modern car diagnostics are done. Then we will cover the P0151 Ford F150 meaning. Then we will cover the O2 sensor and understand how this sensor works. Later on, we will cover the causes of this problem, as well as the symptoms, diagnostics, and the cost involved in fixing the P0151 Ford F150 on your truck. So, if you want to learn more, follow along.

Introduction To Car Diagnostics

Now before we dive into complex topics like the P0151 Ford F150, let’s introduce ourselves to car diagnostics. If you don’t know, modern car diagnostics is the science that you need to know the basics of in order to solve complex problems on modern cars.

Modern cars are a lot more complex than cars in the past. Back in the good old days, mechanics relied on their experience to solve car problems. So, noises, visible damage, and other symptoms helped the mechanic to solve the problems on the cars.

But not anymore. Not that now there are no symptoms at all. But symptoms can be very misleading since nowadays a lot of carmakers introduced a ton of sensors and other components that is there to regulate certain processes inside of the engine.

So, a lot of new and unknown problems appeared once carmakers computerized the cars they make. So, each car has a computer known as ECU or sometimes as ECM or PCM. This engine control unit basically communicates with the sensors inside the car.

It constantly reads the data and evaluates this data. It performs tests on different sensors and once some of these sensors fail, it will trigger a check engine light.

And here you need a tool known as an OBD2 scanner in order to access the computer and read the codes. Like in our case, the P0151 Ford F150 or P0151 Ford Explorer.

Then you will learn the meaning of the code and then you will be able to troubleshoot. And troubleshooting is often done with another tool known as a multimeter. The multimeter will give you the ability to test the components. But more on that, we are going to cover it in a bit. Now let’s learn more about the meaning.

P0151 Ford F150 Meaning

Now as we covered more about car diagnostics and the tools that you need in order to perform diagnostics the right way. We can now slowly move on to the P0151 Ford F150 problem. More precisely, to learn the P0151 Ford F150 meaning. What does this code mean?
Well, the simple definition of this code is “Oxygen O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)”. So, what does this means?

Well, this means that you have a problem with the electric circuit of the first O2 sensor on bank 2. What is important here to note is the location of the sensor.

The location is a common problem when it comes to understanding which of the sensors is bad. So, let’s elaborate more on this.

On each engine depending on the engine design, there could be one or two banks. Usually, inline engines, are also known as straight engines. Namely, straight-4 or straight-6 can only have one bank and that is bank 1.

While on the other hand, engine designs like V6, V8, V10, and V12. Or even the Subaru boxer engines have two banks. This means that there are bank 1 and bank 2.

Bank 1 is the bank where cylinder 1 is located. And bank 2 is the bank where cylinder 2 is located.

In order to understand which bank is number 1 and 2, you need to check on the block and see if there is stamping. On some engines, there is simply the number 1 engraved on the block. Or if you can’t find it, you can look for the firing order of your engine online. There you will be able to find which bank is number 1 and solve the P0151 Ford F150.

What Is An O2 Sensor

Now before we dive into the causes for the P0151 Ford F150, let’s take a look at what is an O2 sensor in general. There are a lot of people that are simply not familiar with this sensor and do not know its purpose. So, let’s elaborate.

An O2 sensor in simple terms is a sensor that measures the level of oxygen inside the exhaust and helps the engine to determine the air-to-fuel ratio. And also, this sensor helps the catalytic converter to work efficiently. In other words, this sensor plays a crucial role and is important just as the MAF sensor because without it being in proper working order, you will face symptoms of a bad O2 sensor that we are going to elaborate on in a bit.

But what is air to fuel ratio? Well, the air-to-fuel ratio in simple words is the mixture of air and gasoline that is injected into the cylinder and then ignited.

The proper A/F ratio should be 14.7:1. This means that there should be 14.1 parts of air for one part of gas.

Usually, the A/F ratio is rich when you do a cold start until the engine warms up. So, after that will smoothen up and will reach the ideal numbers.

And when it happens when you have a bad O2 sensor is that you will not be able to reach these ideal numbers. And the engine will run poorly. It will also throw the check engine light and the code P0151 Ford F150. So, beware of this. But what are the causes for the P0150 Ford F150? Let’s cover this next.

P0151 Ford F150 Causes

Now as we learned the P0151 Ford F150 meaning, let’s move on and cover some of the causes for this problem.

What could be causing this issue? Let’s elaborate on all of the possibilities in-depth in the following chapters and understand more about the root of the problem.

1. Faulty O2 Sensor

Now let’s cover the first cause for the P0151 Ford F150 code. And this is the bad O2 sensor. And frankly, this is one of the most common things that can happen.

The O2 sensor can short inside, stop functioning and produce low voltage. When you have a bad O2 sensor, the output voltage that this component will send to the ECU will be really low.

Which is an indication of a dead sensor. A good sensor should cycle somewhere between 0.1 and 0.9 volts. So, if you go through the RPM the voltage should rise. If it doesn’t, the sensor is probably dead. Still, there are also a few other causes for the problem with the P0151 Ford F150 code and we are going to cover them next.

2. Short In The Electrical Circuit

The second also a very common cause for the P0151 Ford F150 code is a short in the electrical circuit that goes from the PCM to the sensor itself.

You have the wires, and also the connectors that can go bad. There is some wiring that is produced from soy which rodents love to eat and they can damage the wires and cause a short in the circuit.

Also, there are other problems with the connectors. The connectors can corrode and lose contact. So, if the contact for the output voltage from the sensor does not work, you will simply get a 0 volt reading and the P0151 Ford F150 code. So, checking the wiring should be one of your top priorities before replacing the actual sensor since O2 sensors are rather expensive and you don’t want to replace them just like that. Now let’s move on to the next probable cause for the problem.

3. Exhaust Leak

The next probable cause that we are going to elaborate on when it comes to the P0151 Ford F150 code is the exhaust leak. But how can an exhaust leak cause such a problem?

Well, just imagine that the exhaust manifold or the bolts are cracked. A lot of the exhaust gases will escape through these holes.

And if you don’t have a proper flow of gases, the sensor readings will vary and you could get some bad readings.

These readings will trigger the check engine light and this code. So, make sure that you check all the manifolds and bolts and make sure that you don’t have any exhaust leaks in your car. If you do, make sure that you sort them out before you decide to replace the sensor because in most cases, fixing this issue will sort out the problem with the check engine light and the P0151 Ford F150 code.

4. Lean Condition

And the last probable cause for the P0151 Ford F150 code is probably a situation where you have a lean air-to-fuel mixture.

This is the case when you have too much air and too little fuel inside the A/F mix. This is why it is often recommended when it comes to O2 sensors to read some live data.

Live data will give you a lot of information about the sensor and how it works under different types of load. But more on that, we are going to cover later on after we cover the P0151 Ford F150 symptoms.

P0151 Ford F150 Symptoms

So, we learned the common causes for the P0151 Ford F150 symptoms and covered that this is often caused either by a dead sensor or possibly because of bad wiring.

Now let’s move on and cover the symptoms when this code is present. As with every other component when you have a bad O2 sensor and the P0151 Ford code, you will also experience some symptoms as well. So, let’s cover them briefly before we cover the cost to fix the P0151 Ford code.

1. Check Engine Light

The first symptom as you probably assume is the check engine light. Without the check engine light, we wouldn’t even be able to learn about this code P0151.

So, we are not going to elaborate a lot on this symptom since we are already familiar with the problem and this symptom since we diagnosed the P0151 Ford F150 code. Now let’s move on to the next symptom.

2. Poor Engine Work

The next probable symptom that you will notice when you have a P0151 Ford F150 code is poor engine work.

So, what does this mean? Well, poor engine work can be represented in many different ways. But the most common situation, in this case, is the misfires that will be quite common.

The engine will love to run rough and there will be misfires and poor engine idle. This is the case because the A/F sensor is not recording data and is not sending this data to the ECU.

So, when this happens, the engine will not be happy at all and you will notice this by the audible symptoms. And there are also some other symptoms of the P0151 Ford F150 and we are going to cover them in-depth next.

3. Poor Acceleration

The next symptom when you are in this situation and you have a P0151 Ford F150 is poor acceleration.

When you are in this situation, your vehicle will accelerate quite slowly and will feel down on power.

You might feel in this situation that you have 20 horsepower or more loss in performance from the engine. Not an ideal thing. Now let’s move on to the next symptom of the P0151 Ford F150 code.

4. Poor Fuel Economy

The next symptom on our list is poor fuel economy. Yes, that’s right, the fuel economy will get a lot worse if your O2 sensor is not working correctly.

The ECU will try to adjust the air to fuel unsuccessfully and since it doesn’t have the data on the oxygen, it could throw a lot of gas in the mix.

And the more gas in the mix, the worse the situation will be. You will get poor fuel economy, which means more frequent visits to the gas station. Also, there could be possible damage to the catalytic converter because of this type of work.

And catalytic converters are crazy expensive. Costing at least $1,200 and in the worst case, they can cost up to $2,600. So, this is why diagnosing and fixing the P0151 Ford F150 problem quickly might be your best bet. And that’s what we are going to cover next.

How To Diagnose P0151 Ford F150

Now let’s take a look at how you can tackle this problem. So, you have diagnosed a P0151 Ford F150 code. This indicates a problem with bank 2 sensor 1.

Locate this sensor, this sensor is located on the second bank of the engine and it is the upstream sensor located right on the exhaust manifold.

The first thing you need is to inspect the wires. Check the wiring and see if there is any damage. The next thing you want to do is to unplug the connectors and see for rust. Clean the connectors if they are rusted out because this could cause your problem.

If this doesn’t solve your problem, you need to test the wiring with a multimeter. You need to check all three wires. The ground, signal wire, and power wire. Three-wire sensors are most common but there are also two-wire and four-wire sensors. So, you need to find a diagram for the specific one first before you check with a multimeter.

On how you can check with a multimeter, you can see in the video above. In the video, the test is for 4-wire O2 sensors without removing the sensor from the car.

But not all cars are quite easy to work on, so in some cases, you will have to remove it and simulate the test with a torch. An ideal test would be a voltage of somewhere between 0.1v to 0.9v. But the sweet spot when the car idles is probably about 0.4v.

If the sensor does not produce voltage, then this sensor is probably dead and you will have to replace it with a new one in order to solve the P0151 Ford F150 code.

Cost To Fix P0151 Ford F150

So, we learned what is an O2 sensor and how to diagnose a P0151 Ford F150. Now let’s take a look at how expensive it would be to replace the sensor on your car. How much money can you expect to pay to sort this problem out?

Well, in order to tackle this problem you will have to pay at least $150 to replace this sensor if you do this work by yourself.

If you pay for diagnostics and replacement, then the price would probably be above $300. Since diagnostics is often about $120 plus the labor for replacement. So, you get the idea about the O2 sensor replacement cost.


In this article, we have covered quite a bit when it comes to the O2 sensor. First, we learned what is car diagnostics and how it is done on modern cars.

Then, we elaborated more on the problem with the P0151 Ford F150 code and we covered the meaning. We learned the common causes, as well as the symptoms that are present when this code appears. Lastly, we covered the diagnostics and the costs involved in replacing this sensor on your car.