What Are Bad MAP Sensor Symptoms and How to Detect?

Get to know the bad MAP sensor symptoms to prevent severe issues as it significantly affects the overall performance of the engine!

What is a MAP Sensor?

Manifold Absolute Pressure Sensor, commonly known as MAP, is part of an engine’s electronic regulatory system. The main purpose of this sensor is to create optimum combustion in the engine.

As it has a critical role to play in the engine’s working, it is equally important to follow its maintenance guides.

However, sometimes due to the Faulty Manifold Pressure Sensor, the fuel control activity gets disturbed. Therefore, to detect such issues at an early stage, it is important to consider the bad MAP sensor symptoms.

What Does A MAP Sensor Do?

As the name says, the Manifold pressure sensor, which means it, calculates the pressure inside the manifold. In detail, the main work of this sensor is to provide manifold pressure information to the PCM.

Next, the Powertrain Control Module uses this data to determine the amount of fuel injection in the cylinders. It is helpful in controlling the ignition timing, which further prevents spark and thus, protects the engine from any damage.

What Are The Symptoms of a Bad MAP Sensor?

The symptoms of a failing manifold pressure sensor are similar to the problems of low compression or improper fuel injection.

These problems need to be detected beforehand. So, here are certain defects of MAP sensor issues.

Increased emission from the vehicle

When the Manifold Absolute Sensor signals the high load of the engine to the PCM, it increases the release of fuel into the cylinders. Because of this, the economy of the fuel reduces.

Thus, in turn, it causes the emissions of certain chemical components like carbon monoxide and hydrocarbon, which further increases smog in the surrounding atmosphere.

Problem with the emission test

To detect the bad map sensor symptoms, it is highly recommended to get the vehicle check consistently through an emission test.

If the test depicts a large amount of NO, hydrocarbon production alongside low CO2 and high levels of carbon monoxide through the tailpipe, it indicates the issue with the MAP sensors.

Power deficiency into the engine

The map sensor is responsible for signaling the manifold pressure to the PCM. However, if the sensor calculates the depressed load in the engine, it will automatically affects all the further functioning of the engine.

If PCM records low engine load, it would reduce the fuel injection into the cylinders. The engine then won’t remain powerful enough to give the desired output.

No doubt, it will increase the fuel economy but on the other hand, it also raise the temperature of the combustion chamber, thus leading to an increase in the Nitrogen Oxide, which is one of the vital constituents of smog.

See More: How to Boost Engine Power

Acceleration issues

One of the signs of a bad MAP sensor is acceleration issues. As you are driving your car and putting your foot on the gas pedal, you might observe your car hesitating or jerking when accelerating faster.

In bad situations, if you keep giving it gas under these conditions, your car will die altogether. In these cases, the best solution is taking it to a repair shop as soon as possible.

Strange smell

A strange smell from cars is one of the faulty map sensor symptoms. A bad MAP sensor will cause the wrong amount of air and fuel to be mixed in the combustion chamber.

Sometimes there will be a little amount of air and fuel while other times, there will be too much. This improper amount of mixture will create a very strange gas smell.

You will notice this weird smell in the car after your engine has been operating for 2-3 minutes.

Check Engine Light

While driving, the engine control unit continually analyzes all of the sensors in your engine. If a reading of one of these sensors is not in specified range, the check engine light will illuminate.

As a result, if your MAP sensor gives incorrect data to the engine management unit, there will be check engine light on your dashboard.

Below is a list of codes related with the MAP sensor.

• P0068: Throttle Position Correlation
• P0069: Correlation of Manifold Absolute Pressure and Barometric Pressure
• P0105: MAP Circuit Failure
• P0106: MAP/Barometric Pressure Circuit Range/Performance Issue
• P0107: Low Input Manifold Absolute Pressure/Barometric Pressure Circuit
• P0108: High Input MAP Pressure Circuit
• P0109: Intermittent MAP / Baro Pressure Circuit
• P1106: MAP/BARO Pressure Circuit Range/Performance Issue
• P1107: Low Voltage Barometric Pressure Sensor Circuit

Keep in mind these codes might be set by defective sensors or other components. Even if your engine exhibits the symptoms above and displays one or more of the OBD-II codes listed, test the MAP sensor to determine if it is defective.

Under-standard air-fuel ratio

In case the MAP sensor is at fault, it may cause your engine to receive a too-lean air-fuel ratio mixture. And lean mixture like this can create many weird-like signs for your car engine.

On the other hand, MAP sensor problems can lead to excessive fuel injection into your engine while sending a faulty signal to the whole system.

In detail, if encountering this issue, your fuel consumption can go up high, causing driving problems.

Hesitation or stalling or rough idle

This failing map sensor function can be daunting since it’s related to the engine performance. When the car is in idle, things may be more complicated.

Many other problematic parts can cause this, therefore it should be fully evaluated before replacing the MAP sensor.

Misfires

Misfires happen when the combustion process within the engine cylinder fails, highlighted among bad map sensor symptoms. This can occur as a result of an incorrect air-fuel combination or a faulty spark.

Listening to your engine may help you detect misfires. Misfires may be to blame if you hear little bumps or if it doesn’t sound as it typically does.

Backfires

Backfires occur when the gasoline is not properly combusted. If the fuel in the combustion chamber is not ignited, it may wind up in the exhaust pipe.

As you can expect, the exhaust pipe gets extremely hot, which might ignite the air-fuel combination within. This may result in loud bangs from the exhaust system and cause your mufflers, etc., to burst.

Unusual fuel consumption

Among symptoms of bad MAP sensor, unusual fuel consumption is understandable since the sensor is working improperly.

A defective air-fuel combination created by a malfunctioning sensor will influence the fuel consumption. If you observe that your automobile is using less or more gasoline than usual, it might be due to a defective MAP sensor.

How To Fix A Bad MAP Sensor?

Here are some elements you should check before bringing your car to an auto shop to replace the sensor.

Hose

In some cars, a hose links the intake manifold and the MAP sensor. So you should know whether the MAP sensor hose is intact and connected or not.

In addition to checking the sensor hose, check that the port is free of debris and carbon deposits, which can block the hose and result in wrong sensor readings.

Electrical

Check the wiring and connector. The wiring between the MAP sensor and ECM should be intact. Chafing could result in short circuits and breaks could result in open circuits. 

Similarly, the connector should be securely connected, and the pins should be straight and clean. Bent pins and corrosion can cause sensor signal problems.

Sensor

If the sensor is installed correctly, both to the intake manifold and electrically, use a vacuum gun and a voltage meter or a scan tool to check.

You will have to look up a chart to measure voltage against full vacuum and no vacuum. If the chart gives a result that is not similar to the output, it’s time to replace the sensor.

How To Replace A Bad MAP Sensor?

The steps to replace a failed sensor vary from one vehicle to another. However, some basic procedures are almost the same.

Take these notes below as your reference for the next replacement project. If you have less experience to mechanic self-projects, consult a professional about any details.

• The sensor should be located on the intake manifold, either close to or on top of the throttle body, or on the intake manifold itself.
• Remove any screws or nuts holding the sensor in place.
• Disconnect the electrical connection. Avoid using force since it may contain a locking tab that must be removed before it can be unlatched from the sensor.
• Disconnect the vacuum hose from the sensor. The suction pipe should be replaced with a new hose.
• Examine the distinctions between the new and old sensors.
• Reconnect the suction hose if required.
• Reconnect the sensor’s electrical connection.
• Replace any screws or nuts keeping the sensor in place.
• Check each connection to make sure they are stable.

Check out this video from DA64W DIY to learn more about how to test MAP sensor with multimeter!

FAQs on MAP Sensor

Wrapping Up

We’ve discussed some bad MAP sensor symptoms and several vital elements to check if there is any problem with this sensor.

If you have any questions related to this topic, feel free to leave them in the comment section and we will discuss them further.