Symptoms of Bad MAP Sensor, Troubleshoot & trick

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works

The engine’s electronic regulation system would be paralyzing without the MAP sensor. One of its key purposes is to facilitate a more efficient burn cycle. The air-fuel mixture ratio is controlled by the powertrain control module (PCM), which receives a reading from the air pressure sensor in the intake unit.

Due to its importance to the engine’s performance, it must be working properly.  When this sensor malfunctions, the ECU will receive an erroneous reading, resulting in an incorrect air-fuel mixture. You can find DTCs with an OBD2 Scanner for DIY to determine it. Otherwise, the engine’s performance will be hampered as a result.

Common observable symptoms

This article will cover the signs of malfunctioning MAP sensors, typical problems, MAP sensor techniques, and the best ways to remedy them. Before learning the troubleshoots, let’s learn about the common symptoms first. 

1. Weak Engine Power

The automobile computer receives a low engine load signal from an air pressure sensor in the manifold that detects low pressure in the intake system. It then tries to make up for this inefficiency by lowering the fuel ratio that is injected into the engine.

As a result, fuel consumption will rise more than normal, but engine performance will deteriorate. When the engine’s fuel ratio is restricted, the combustion chamber heats up.  Consequently, the engine’s nitrogen oxide generation rises following that particular condition.

2. Fuel Consumption on Poor Mileage

The air pressure sensor in the manifold indicates the intake system has a high level of pressure. As a result, the fuel delivery system in the engine will be boosted. What does this mean to you? Fuel usage will rise to compensate to follow the signal while you’re still experiencing pool engine performance.

3. Emission Inspections Failing

The failing emission inspection process is one of the most prevalent symptoms of a faulty MAP sensor in diesel and gasoline engines. Emission tests will fail a vehicle with a subpar MAP in both gasoline and diesel form. Excessive carbon monoxide, high hydrocarbons or excessive production of nitrogen oxide, may be detected in the tailpipe output. Even if the failure isn’t consistent, it’s still a red flag for you.

4. Air-Fuel Mixture Becoming Rich or Lean

An air-fuel mixture having a higher amount of gas is called a “rich” mixture. Toxic buildup on the spark plugs, terrible gas mileage, and a noxious gas smell from the tailpipe are all possible consequences of this rich condition. This certainly causes the MAP bad sensor.

On the other hand, a lean mixture is one in which the fuel and air are not properly balanced. This will cause the combustion chamber to overheat, resulting in engine damage in a matter of minutes. It emits harmful gasses including nitrogen oxides and carbon monoxide. A leaner mixture can totally knock the engine. If this happens, the engine could be seriously damaged.

5. Misfiring Issues

You might have wondered whether a bad MAP sensor can cause engine misfiring. It’s possible that the combustion process will be compromised if a vehicle’s air-to-fuel ratio is richer or leaner than the normal requirements. Misfire can occur if the cycle of combustion is hampered by those factors.

6. Rough Engine Idle

The cylinders will run out of gas or air if the air-to-fuel ratio is richer or leaner. Even random cylinder misfires might result from this condition. Rough idling and even random cylinder misfiring can occur as a result of insufficient fuel injection starving the engine of fuel.

7. Hard Engine Starting

If the fuel mixture is too rich or too lean, the engine will be difficult to start. It is possible that the manifold air pressure sensor may malfunction if the engine can only start if the gas pedal is hit. It’s most likely the reason behind the hard engine start and it’s time to check the air pressure sensor in the manifold.

8. Engine Acceleration Problems

These are the indications of a faulty MAP sensor in a gasoline or diesel engine. All of them indicate that the combustion chamber has an insufficient air/fuel combination. Alternatively, it could signify that the engine has difficulty adapting to a sudden shift in air supply. Consequently, The motor may become stalling, bogging, hesitating, or stumbling when you accelerate constantly.

9. MIL Coming On

When the MAP sensor malfunctions in a car built after 1996, an error code will appear on the dash. Typically, the check engine light or Malfunction Indicator Light(MIL) will come on if any of these fault codes are present. When a turbocharger or supercharger is installed, the MAP sensor can also malfunction. When you’re using a Professional obd 2 scanner to retrieve the DTCs, these codes might appear if you have a malfunctioning MAP sensor:

  • P0106
  • P0107
  • P0133
  • P0299 

The DTCs or error codes related to MAP sensors can be caused by sensor or circuit issues to correlation or range faults. Each model or year make might have slight differences in this area. They should be addressed first before clearing or resetting the DTCs.


How To Know If You Have a Bad MAP Sensor

Maintaining a properly working MAP sensor is an essential aspect of your car’s upkeep. If you find those symptoms, check whether or not you have a malfunctioning MAP sensor with these tests/inspections:

Wiring Inspection

Start by inspecting the connector and the wires that are connected to it. The pins must have straightly good contact, and the connector should be firmly attached. MAP sensor signal difficulties might be caused by corrosion or bent pins. The wiring of MAP and ECM  should be properly connected intact as well. Any damage or chafing in this installation can cause short circuits. 

Home Inspection

A hose connects some MAP sensors to the manifold. Ensure the MAP sensor’s hose is properly attached and intact. To ensure accurate MAP sensor readings, make sure the port is clean from any dirt and contaminant. 

MAP Sensor Unit Inspection

Make sure that the sensor and intake manifold are correctly connected by using a scan tool like Autel MS906 or voltage gauge and vacuum gun to examine the MAP sensor output. You’ll need to check the user’s manual book if you want to compare voltage measurements with and without a vacuum. The MAP sensor should be changed if its output does not match the tech requirement. 

Troubleshooting MAP Sensor

When it comes to troubleshooting MAP sensors, we’d be dealing with two major solutions: testing and replacing. When you’ve tested the MAP sensor and found it malfunctioning, then replacing the sensor unit would be the obvious solution.

Testing The MAP Sensor

You can definitely perform your own MAP sensor testing or use a scanner like Foxwell NT809 to get the trouble codes. How do we go about conducting the tests? In most cases, the MAP sensor is attached to the intake manifold. You can follow these steps to test your MAP sensor:

To gain complete access to the MAP sensor, remove any surrounding parts. 

  1. Remove the MAP sensor’s electrical harness.
  2. Inspect the connecting pins for corrosion.
  3. Use a multimeter or a voltmeter to check the connectors.
  4. Check the external connector using a lead probe connected to the ground. It should be able to supply the correct voltage, typically 5V.
  5. Verify that the computer is properly grounded while measuring the voltage at the terminal on the exterior.

Fixing and Replacing MAP Sensor

If the MAP sensor is actually malfunctioning, get it repaired or replaced as soon as possible to get the most power out of your engine. Replacing a MAP sensor is the sole solution to a MAP sensor problem. Fortunately, replacing a MAP sensor is a straightforward process that anyone can perform. How to proceed is as follows:

  1. Detach the negative battery terminal 
  2. Find the MAP sensor typically on the intake manifold or the throttle body, depending on your car
  3. Detach and remove anything that might be preventing you from getting to the MAP sensor, and then plug it back in.
  4. Disconnect the power lines.
  5. Unscrew the sensor’s mounting screws.
  6. The new sensor should be installed in reverse order and you’re done
  7. You can clear the code with the scan tool like Innova 5610 if you like


A malfunctioning MAP sensor is indicated by a number of symptoms. If you notice two or more of the symptoms listed above, you should check and test your MAP sensor. Always be on the lookout for these symptoms so that you can catch and correct the problem before it becomes a costly repair charge.

To check faulty MAP sensors, you can use a scanner to perform an inspection on the sensor or get professional assistance from a mechanic.

Symtoms of a Bad Map Sensor | How To Fix Bad MAP Sensor |Bad Map Sensor Solution | Bad Map Sensor |
5 1 vote
Article Rating
Notify of
Inline Feedbacks
View all comments