Home Diagnosis and TroubleshootingElectrical System and Electronics MAP Sensor Symptoms – How To Notice Them?

MAP Sensor Symptoms – How To Notice Them?

by Jordan Harris
MAP Sensor Symptoms

Are you noticing that your fuel economy has gone a lot worse lately and the exhaust reeks of gasoline? If this is the case and you are in this situation, you might be noticing MAP sensor symptoms on your car. But you shouldn’t worry because we are going to help you out with this problem.

Having a problem like this can be a frustrating thing to deal with because the whole engine would be bugged out. Meaning that the engine will work really strangely and you will not be able to tell what is the problem. These gremlins will make scratch your head. But the most important for you is to learn the symptoms.

Detecting a symptom is one of the most crucial things you can do. I’m telling you this because based on these symptoms you will be able to tell if the symptoms that you have noticed are bad MAP sensor symptoms or something else could be the problem. This is the process of elimination. You eliminate the possibilities and then you end up with one or two possible outcomes, and one of them is a bad MAP sensor. But what is this sensor? That’s what we are going to talk about.

First, we are going to cover what is the MAP sensor and why it is so important. Then we will discuss the MAP vs MAF sensors and whether they are the same. After we will discuss the MAP sensor symptoms in depth and then we will learn how to diagnose the problem, as well as the costs involved in this work. So, if you want to learn more, follow along.

What Is The MAP Sensor?

So, before we dive into the MAP sensor symptoms let’s first start with the basics. Not everyone here is familiar with what this sensor is and the role it is playing in the internal combustion engine. So, we need to familiarize ourselves with this sensor and learn more about it. If you are already familiarized you can jump to the symptoms. If not, keep up with us.

The MAP sensor is an acronym for Manifold Absolute Pressure Sensor. You can guess what MAP is for a whole day, but when you know what it means you get the idea of what it is probably doing. But either way, let’s elaborate in-depth.

This sensor is usually mounted to the intake manifold. But sometimes its location can even be on the firewall. Depending much on the application. So, for the exact location, you will need to google out your engine and the location to get the right input on where it is located.

Nevertheless, this sensor is usually found in vehicles that are fuel-injected. Meaning that you will not find this sensor on vehicles that are carburetted because these cars do not have sensors. Also, you will not find it on modern vehicles that have MAF sensors.

The MAP sensor is mostly used on vehicles from the ’90s and late ’80s before the MAF sensor was introduced. But they are still used on some new cars that are turbocharged.

This sensor is quite an important piece of the puzzle and helps the work of the engine immensely. Without it, the engine would simply bug down and work strangely. You will instantly start to feel the MAP sensor symptoms when this sensor is not working well. But what is the task of this sensor in general? Well, that’s what we are going to cover next.

What Is The Purpose Of This MAP Sensor?

Before we dive into the MAP sensor symptoms, let’s first learn more about the task this sensor has in an internal combustion engine. We covered the basics above and we learned that this sensor is located on the intake manifold and we still didn’t understand what is the real purpose of this electronic device. But we are going to elaborate now in depth.

This sensor is installed to measure the intake flow. This sensor is directly communicating with the ECU which is the car computer. Then with the data this sensor receives, the computer is determining what is the air density in the intake and the mass flow rate.

Then based on this information about the air density, the computer is determining how much fuel to dump into the cylinders in order to achieve optimum combustion in the engine. Also influencing the ignition timing based on this information the ECU receives from this sensor mounted on the intake manifold.

As you can see, this sensor is doing everything to make your engine run smoothly and without any hiccups. Because if it doesn’t work as it should, you will start to notice the MAP sensor symptoms that we are going to cover later in the article.

But are you confused with the terms MAP and MAF? Some people use these terms interchangeably but they shouldn’t do this practice. In the following chapter, we are going to cover precisely that and learn the similarities and differences between the two and then we will discuss the bad MAP sensor symptoms.

MAP VS MAF, Is This The Same Sensor?

Another thing that we want to discuss before we cover the MAP sensor symptoms is whether or not MAP and MAF are the same sensors? Many people are thinking that they are and are using these acronyms interchangeably. But that isn’t quite correct. And we are going to explain now how naming is done right.

The MAP sensor is referring to the manifold absolute pressure sensor and MAF is referring to a mass airflow pressure sensor. This is not the same in reality, even though they basically do the same thing and are measuring the intake gasses.

Cars do not have both a MAP and MAF sensor unless they are turbocharged. If they are naturally aspirated they have only one sensor, MAP, or MAF in 99% of the cases.

On older vehicles, the MAP sensor is the standard. But in newer cars, they all have MAF sensors. MAF sensors offer a number of advantages over MAP sensors. Namely, better accuracy.

MAF sensors are far more accurate than MAP sensors and that’s why they are mainstream and every carmaker is using them. Even though as we said, turbocharged gasoline and diesel cars have them. As well as some gasoline cars that have the MAP sensor in case of a MAF sensor failure happens.

In addition to this, the mounting place is different between the two. MAF sensors are located behind the intake box. While the MAP sensors are located on top of the engine intake manifold.

Now as we cleared some things, let’s focus on the MAP sensor symptoms and see what you can expect if your MAP sensor has failed. So, if you want to learn more, follow along.

Bad MAP Sensor Symptoms

Now let’s move to the main topic and that is the MAP sensor symptoms. As we know, every component before it fails is starting to show some symptoms.

These symptoms are indicators that something could go wrong pretty soon. And the sooner you pick them up and understand them, the better for your budget since you will avoid some other possible problems that might pop up because of this issue. Namely, the problem with the MAP sensor can affect a number of components like the spark plugs, fuel injectors, O2 sensor, catalytic converter.

MAP Sensor Symptoms

There could be a ton of problems that might rise up if you don’t learn the MAP sensor symptoms that we are going to cover in the following chapters. So, if you want to learn more follow along.

1. Check Engine Light

The first of the MAP sensor symptoms that you will notice is the check engine light. Remember that the ECU is observing the work on all of the sensors. So, if the ECU senses that there is something wrong with some of the sensors it will throw that check engine light on the cluster.

You can’t know why this light is there without some deeper investigating. For this, you will need to scan the car for errors and see if there are any codes connected to the MAP sensor. This means diagnostics need to be performed on the vehicle to determine why this light is flashing. If it’s because of the MAP sensor, you will have to replace the sensor. Now, let’s move to the other MAP sensor symptoms.

2. Rich Air To Fuel Ratio

The second in the list of MAP sensor symptoms is the one with the rich fuel to air mixture. When the car is running rich, it means that in the combustion there is too much gas and too little air. So, what happens is that some of the gas doesn’t burn and ends up in the exhaust.

Ruining the performance of the car in the process and also damaging the catalytic converter and the oxygen sensor. You will also feel the smell of gas in your cabin and in the rear. That’s why you don’t want these MAP sensor symptoms. Now, let’s move to the following symptom.

3. Lean Air To Fuel Ratio

Now let’s cover the second in the list of MAP sensor symptoms and this is the lean air to fuel mixture. This is completely the opposite of the rich air to fuel mixture.

In this situation, there is too little fuel dumped into the cylinder and a lot of unmetered air. The air is prevailing, thus, ruining the performance of the engine. This type of engine work will affect the spark plugs and the O2 sensor. It can cause blistering to appear.

In this case, when you are experiencing MAP sensor symptoms like this you will have a problem keeping the engine in check, it will often want to stall since there is not enough fuel inside. Now let’s move on to the next.

4. Misfires

The third in our list of MAP sensor symptoms are the misfires that often happen this sensor fails. This is mostly because of lean or rich air to fuel mixture.

When these misfires occur, you will notice how there are ticks from the engine cylinders. Also, on the exhaust, there will be some pops and bangs. This is because the explosions inside of the cylinders are not smooth and the overall engine work is really poor.

These misfires can also affect components like engine coils, spark plugs, engine valves, you name it. That’s why it is very important to sort out this problem quickly if you don’t want to have problems in the long run. Now, let’s continue with the MAP sensor symptoms.

5. Bad Fuel Economy

The bad fuel economy is another in our long list of MAP sensor symptoms that often appears along with the rich air to fuel mixture symptom.

Whenever the car is running rich, worsening in the fuel economy is understandable and you can expect that the MPG rating will drop significantly. In most extreme cases, even by 5 or more MPG. And that is something that can hit your wallet really bad. So, beware of the MAP sensor symptoms. Now let’s move on to the next one.

6. Inability To Start The Engine

Another in the list of MAP sensor symptoms is the inability of the engine to start. This is the case if the fuel to air mixture is too lean. I mean extremely lean and there is little to no gas pumped in the combustion chamber.

If this is the case, then the engine will not even like to start at all. You will continuously crank the engine until eventually starts. And by doing this, you could damage the battery. So, when this happens it is not recommended to drive a car like this and try to sort out the problem.

7. Engine Down On Power

Another in the list of MAP sensor symptoms is the symptom when the engine is down on power. And if the engine is running lean because of this problem will be significantly down. Meaning that it will not feel as it did before the problem occurs.

This problem could also be attributed to bad engine coils, bad spark plugs, and even bad injectors and a bad fuel system. So, whenever this happens, the best would be to perform deep troubleshooting and diagnosing with a diagnostics tool. But more on that in a bit after we cover the MAP sensor symptoms.

8. Engine Stalling

The last in the list of bad MAP sensor symptoms that we are going to cover is the engine stalling issue. Whenever there is a problem like this on your car you will also experience some engine stalling issues.

But you can never know what could be causing the problem unless you diagnose the issue with proper equipment. But how you can diagnose a MAP sensor based on the MAP sensor symptoms that we covered?

Well, that’s what we are going to cover in the following chapter where we will discuss everything about diagnosing the issue quickly and effectively at home with an OBD2 device and a multimeter. So, if you are interested to know how it’s done, follow along.

How To Diagnose & Replace A Bad Map Sensor?

We finished with the MAP sensor symptoms, not we came to the important bit and that is how to diagnose this problem. Diagnosing this issue could be pulled off by using two different methods.

The first method is to grab yourself an OBD2 scanner tool. This is a diagnostics tool as you know, with this tool you can access the car computer and scan the car for codes.

You can find these small tools on Amazon for a really good deal and they are basically your lifesaver. You just plug the scanner in the OBD2 port that is usually located above the gas and brake pedals and let it scan the car for codes.

If there is a problem with the MAP sensor, you will be greeted with one or more codes. The codes associated with this problem are P0068, P0069, P0105, P0106, P0107, P0108, P0109, P1106, and P1107. There could be other codes as well, but these are the most common ones.

If you got a code similar to these, you can move on to diagnose the sensor with a multimeter tool. For this, you will need to start the car and connect the multimeter with the sensor, when you apply the throttle, then the voltage should rise if the sensor is good.

For more details, you can check the video that we attached above and see how the multimeter testing is done the right way. The explanation starts at 3:10 seconds. It is not a complex thing to do, you only need a little bit of electrical knowledge.

Replacing this sensor is quite simple, plug and play. Just unplug the old one and plug the new sensor in and you will be good to go. No more MAP sensor symptoms.

Cost To Replace A MAP Sensor

We covered the MAP sensor symptoms and we learned how you can diagnose the problem quickly and effectively, now let’s see what will cost you to replace this sensor. As we all know, everything revolves around the price and some parts can be really expensive to replace on a car.

Most people are running away from these problems. But they will come stronger one day and will bite you by the hand. And you don’t want that. Imagine that you are delaying and delaying the repair on this problem and the problem becomes bigger and bigger and eventually the sensor is failing completely.

This is not one of the experiences that you want to have because the whole engine work would be messed up, the engine will run either rich or too lean. Absolute nightmare. That’s why replacing this part and paying the costs is the smart thing to do. But how much does it cost to replace a MAP sensor on your car? Let’s elaborate.

On average, the repair for this sensor is about $240. This price is not that cheap though, and you definitely want to do this cheaper right? Well, the way you can do it is to buy the part yourself and replace it yourself.

By doing this you will save about $100 or so. Which is not a lot, but also not a small amount of money. It really depends much on how good you are at diagnosing the issue. If you are sure about it and you know that the sensor is faulty, just go to your local parts store and grab one. No more MAP sensor symptoms on your car and you will be able to enjoy your car once again.

What If I Continue Driving Like This?

Now after we covered the MAP sensor symptoms in-depth, let’s focus on some other topics. Namely, the question of whether something is going to happen to your engine if you continue like this with a faulty MAP sensor? Is there any possible engine damage that could happen if you keep delaying this fix?

MAP Sensor Symptoms

The short answer is no. Damage to the engine will not be present at least not on the block. But other components like engine valves that are located on the head could take the toll as well as the spark plugs, coils, catalytic converter, and O2 sensors. Basically, all these components are affected by this poor engine work. Especially the catalytic converter if the engine runs rich for too long.

A new catalytic converter is a significant fortune (as is the case with a 2000 Jeep Cherokee catalytic converter or the 2008 Infiniti G35 catalytic converter or a 2008 Lexus ES 350 catalytic converter). About $1,500 to be more exact. And that is a lot of money. Not to mention that the car could also stall and not start when you need it the most. That’s why you shouldn’t ignore the MAP sensor symptoms.

MAP Sensor Facts

  • The manifold absolute pressure (MAP) sensor is used in fuel-injected engines to calculate fuel injection for optimal air-fuel ratio by monitoring intake manifold pressure information.
  • Turbocharged engines use both a MAP and a mass airflow (MAF) sensor.
  • The MAP sensor is typically located on the intake manifold, and it performs as a barometric pressure sensor as soon as the key is turned on.
  • The MAP sensor helps the engine control module (ECM) determine when the ignition should occur under varying engine load conditions.
  • A faulty MAP sensor will affect an engine’s air-fuel ratio and can cause rough idle, poor fuel economy, slow acceleration, surging, stalling, lack of power, and failed emissions test.
  • MAP sensors can fail due to contamination, clogged or leaky hose, extreme vibrations, and electrical connectors that melt or crack from overheating.
  • The ECM combines manifold pressure readings from the MAP sensor with data from other sensors to calculate air density and accurately determine the engine’s air mass flow rate for optimal air-fuel ratio.
  • Some common MAP sensor fault codes include P0068, P0105, P0106, P0107, P0108, P0109, P0069, and P1106.
  • To troubleshoot a MAP sensor, inspect its physical appearance, check the connector and wiring, inspect the hose, and test it using a digital multimeter set to 20V and a vacuum pump.
  • To replace a faulty MAP sensor, consult the manufacturer’s service manual for instructions, and once the faulty sensor is removed, install the new part by connecting the vacuum hose and electrical connector, and securing the screws or bolts that hold the sensor in place.

Conclusion To MAP Sensor Symptoms

In this article, we have covered quite a bit when it comes to MAP sensors. We covered the basics of these MAP sensors and what is their main role. As we noted they are very important because they measure the gas flow inside of the intake manifold.

Then we covered the MAP sensor symptoms. These symptoms include lean or rich air to fuel mixture, misfires, poor engine work, and increased fuel consumption.

Lastly, we focused on solving the problem and learning what you could do to tackle this issue. We learned how a bad MAP sensor is diagnosed and replaced. And not to forget that we also elaborated on the cost to replace this sensor.

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