Here are 10 Signs of a Bad MAP Sensor and Their Replacement Cost.

The manifold absolute pressure sensor, also known as the MAP sensor, is an important part of the car’s engine management system.

The MAP sensors are found in fuel-injected vehicles. Their primary function is providing information to the Powertrain Controller Module (PCM/ECM), about the pressure inside the intake manifold.

As with all sensor components in your vehicle's engine, the MAP sensors will experience wear over time. Damaged sensors can transmit incorrect data to the engine control module. How can a MAP sensors fail? Here’s a quick overview of the signs to look for:

Bad fuel consumption and a check engine lamp on the dashboard are two of the most obvious signs that a MAP sensor has failed. Other signs include a misfiring and stalling of the engine. You may also notice a rough idle or trouble starting.

A problem with the manifold absolutepressure sensor (MAP), can lead to improper combustion. This will damage the engine and cause performance problems.

Below is a list that explains the symptoms most commonly associated with a defective MAP sensor.

Índice de Contenido
  1. Bad MAP Sensor Symptoms
    1. 1. Verify Engine Light
    2. 2. Lean Air-fuel Mixture
    3. 3. Rich Air-fuel Mixture
    4. 4. Or Rough Idle?
    5. 5. Mistakes
    6. 6. Elevated Emissions
    7. 7. Bad engine performance
    8. 8. Backfires
    9. 9. It is a difficult condition to start
    10. 10. Modified fuel consumption
  2. MAP sensor location
  3. Price of MAP sensor replacement
  4. Diagnostics for a bad MAP sensor
  5. FAQ on MAP Sensor
    1. Do I have to drive my car with bad GPS?
    2. What can you do to tell if your map sensor is defective?
    3. What is the cost of fixing a map sensor
    4. What can be done to remove a sensor from a map?

Bad MAP Sensor Symptoms

1. Verify Engine Light

Check Engine Light

While you are driving your car, the engine control module monitors the status of all sensors within the car's engine. If one of these sensors’ values is out of the specified range – the check engine light will show up.

If your MAP sensor is sending incorrect information to the engine control units, the check engine lamp will be displayed on your dashboard.

2. Lean Air-fuel Mixture

Spark Plug Misfires

The MAP sensor’s primary purpose is to measure the air pressure in the intake manifold to calculate the right air-fuel mixture for your engine. A bad sensor can lead to your engine getting a low-quality air-fuel mix.

You may experience strange engine symptoms when you use a lean fuel mix. These symptoms can be found further down.

3. Rich Air-fuel Mixture

Car Rich Mixture E1609804774815

It is the same for both sides. A bad MAP sensor can cause an engine control unit (engine controller) to inject too many fuels into the engine.

A rich air-fuel mixture will not only cause your fuel consumption to go up – but it will also cause performance problems.

4. Or Rough Idle?

Car Engine Rough Idle

If your air-fuel mixture is too rich or too lean caused by a faulty MAP sensor, you may notice problems at the engine’s idle. It is extremely sensitive when the engine idles, so you might notice problems at idle.

This can be caused by many other parts that are also defective. Before you replace your MAP sensor, it is important to diagnose the problem.

5. Mistakes

Car Misfires

Engine cylinder failures cause misfires. A bad air-fuel mixture, or even a poor spark can lead to misfires. The MAP sensor can cause your air-fuel mixture so poor that misfires may occur.

Your engine's sound can be used to detect misfires. If you can hear small bumps or if it doesn’t sound like it usually sounds – it may be caused by misfires.

6. Elevated Emissions

Cars Emission Test E1609865644244

The manifold absolute pressure sensor, or MAP, can be damaged and send an inaccurate signal to the powertrain controller module (PCM) indicating high engine loads.

The air-fuel combination must be perfectly balanced to ensure a high level of emission. A slight mistake with the MAP sensor could cause fuel mixture problems.

7. Bad engine performance

Slow Car Acceleration

A faulty fuel mix can cause engine performance drops, as we discussed earlier. Although a lean mixture will usually cause a decrease in engine performance, it is possible to also be caused by an excessively rich mixture.

A bad MAP sensor can cause misfires, which in turn can lead to poor engine performance.

8. Backfires


If the fuel entering your engine isn't properly combusted, it can cause backfires. If the fuel does not get ignited properly in the combustion chamber it can end up in the exhaust pipes. The exhaust pipe heats up, which can cause the fuel mixture to ignite.

The exhaust system will emit loud bangs that can lead to your car catching on fire. If you're not careful, it can set your car on fire.

9. It is a difficult condition to start

Starting Car

Also, a faulty MAP sensors can cause problems with car starting. The car’s trip computer uses the MAP sensor to determine the air pressure before starting the engine.

Engines are sensitive to the proper air-fuel mix at the beginning moment. Therefore, an incorrect reading may cause too much fuel to be delivered and prevent the engine from starting.

10. Modified fuel consumption

Fuel Consumption

It is probably the most straightforward if you go through the rest of the article. The fuel consumption will change if the MAP sensor is defective.

You may notice your vehicle using less or more fuel. This could be due to a defective MAP sensor.

MAP sensor location

Map Sensor Location

Most car models have the MAP sensor located at the intake manifold. It can also be installed on the car’s body on a vacuum hose going from the intake manifold.

The position of the MAP sensor depends on your car’s design, and it is recommended that you check the exact position of the MAP sensor in your car in the service manual.

Price of MAP sensor replacement

The cost of replacing a MAP sensor is on average between $60 to $170 depending upon the vehicle model and labor expenses. The labor costs for the sensors are between $30-$70 and $30-$70 respectively.

It is possible to replace the MAP sensor on almost all car models at your home. You can save money if you are familiar with cars.

Diagnostics for a bad MAP sensor

Car Diagnostic

First, observe the symptoms of your car and conduct a test to determine if it has a faulty or failed MAP sensor.

Connecting a diagnostic scanner is the best way to test the MAP sensors. You should see a reading close to one bar, or 14.5psi when the engine is off with ignition turned on.

You can watch this video to learn how to test the MAP sensor. Testing of the MAP sensor.

Below is a step-by–step guide you can use to test and diagnose the problem with your vehicle's MAP sensors.

  1. Check your vehicle's service manual to locate the MAP sensors.
  2. Make sure the vacuum hose connected to the MAP sensor has been properly connected and in good condition.
  3. Make sure you check the condition of the wires and connections.
  4. You can clean your sensor using an electronic cleaner. Then, recheck the results with your scanner.
  5. After testing, test the MAP sensor. These instructions.
  6. You should measure the connections between the engine control module and the MAP sensors.
  7. Repair wirings or replace the MAP sensor if it is defective.

FAQ on MAP Sensor

Do I have to drive my car with bad GPS?

Bad map sensors can cause the mixture of air and fuel to become too rich or lean. Bad map sensors can lead to engine performance issues. It is best to not drive your car with one. It is possible to drive slow and steady until your car repairs are completed.

What can you do to tell if your map sensor is defective?

The most common way to tell if your MAP sensor is bad is by looking at the check engine light in your dashboard. You can use a diagnostic tool to check what the MAP sensor is sending to the ECU.

What is the cost of fixing a map sensor

The MAP sensor is usually relatively inexpensive and can be replaced at your home. The sensor costs between 30-70$, and labor is around 30-100$.

What can be done to remove a sensor from a map?

Yes, there will often be soot and other crap on the MAP sensor’s measure head over time. You can clean this with an electric cleaner. You must be careful not to damage the sensor. You may have to change the sensor in some instances.

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