A good, working air flow sensor is essential to your car or truck operating efficiently. But what if you have a bad mass air flow sensor? Can you drive with a bad mass air flow sensor?
You can drive with a bad mass air flow sensor, but only for a very limited time. If you drive for too long with a faulty sensor, it can lead to serious engine problems.
A bad mass air flow sensor will cause different drivability issues. You can experience a lack of power, stalling, poor acceleration, and even a no-start engine while driving your car. A faulty mass air flow sensor will also cause the ‘Service Engine Soon’ or ‘Check Engine’ light to turn on.
Read on to learn how a bad mass air flow sensor can affect your car or truck’s efficiency and what you can do to solve this problem.
Can You Drive with a Bad Mass Air Flow Sensor?
It is possible to drive with a bad mass air flow sensor for a limited time. However, you should not drive with a bad mass air flow sensor because it can lead to engine issues.
If you ignore what this sensor is telling you, the problem will worsen. It can even lead to severe damage to the car’s engine, forcing you to repair or even replace it.
Repairing a car engine is a lot more expensive than repairing a problematic mass air flow sensor. Replacing an engine is even more expensive. If you replace the sensor now, it will only cost you around $200. But if you are forced to replace the engine, the cost could reach up to $7,500.
So, don’t ignore what the mass air flow sensor is telling you. Have it cleaned, repaired, or replaced now, instead of later. This is rather an easier and cheaper option compared to repairing or replacing the engine of your car.
A bad mass air flow sensor will not prevent your car from running. You can still drive your car, but it will be less efficient.
How long can you drive with a bad mass air flow sensor? You can still drive your car with a bad mass air flow sensor for a while. But it’s not advisable if you do it for an extended period. If you continue driving, mechanical damage to the engine could develop because you are forcing it to run in a lean air-to-fuel condition.
A malfunctioning mass air flow sensor will not send any airflow information to the PCM. So the PCM will not be able to control the amount of fuel it sends to the engine. Therefore, the engine may idle roughly, or it may not even idle at all.
In addition, if the PCM continuously sends the wrong amount of fuel to the engine, the air-to-fuel ratio will either be too rich or too lean. You will notice this if you see black smoke coming out of your tailpipe or if your fuel consumption has abruptly changed.
How can the hot wire of a MAF sensor go bad? There are many reasons why this hot wire will not function properly:
- It gets dirty from the oil residues coming from an over-oiled reusable performance air filter
- Potting compound
- Spider webs
- Other sources of dirt that serve as the wire’s insulation
You can easily and inexpensively solve this problem by simply cleaning the MAF sensor. But if you ignore and neglect it, it will lead to more extensive engine problems.
Symptoms of a Bad Mass Air Flow Sensor
If the MAF sensor doesn’t properly work, it will cause problems similar to low vacuum or low compression issues. It can also manifest as low fuel pressure, which would make you think that the problem is with the fuel pump.
Other symptoms will also tell you if this sensor is going bad. These symptoms include the following:
- There is some jerking or hesitation during acceleration
- The engine drags or hesitates while it is idling or under load
- Engine hiccups
- The engine is hard to start, and the alternator has difficulty turning it over
- Engine stalls or stops right after starting
- The idling is either lean or rich
If you have isolated the problem and are sure that it is the MAF sensor, take it to a professional mechanic. They will be able to make a full computer diagnosis of the problem.
Typically, a defective MAF sensor has a certain code that will show when the computer is diagnosing it. This problem is relatively easy to determine by using computer diagnostic equipment.
Check the Air Flow Sensor by Disconnecting It
When you are not sure if it’s a bad air flow sensor that is causing the problem, you can unplug it and run your car or truck. Just drive it to a short distance and observe if it runs properly with the MAF sensor unplugged. If your car runs correctly, the MAF sensor is the one at fault.
Have it cleaned or replaced as soon as you can. Don’t drive your car as you usually do until you clean or replace the MAF sensor.
Why Do MAF Sensors Go Bad?
The most common reason why MAF sensors go bad is contamination. This device is exposed to air, oil, dirt, and all kinds of debris. Foreign matter can penetrate the sensor, and its internal parts get contaminated. When the sensor is dirty, it will malfunction.
When you notice a sluggish performance of your car or truck, the culprit could be a bad mass air flow sensor. If the idling is rough, or if your car or truck stalls after starting, or if you are experiencing poor acceleration, check the MAF sensor. That could be your problem.
When Can You Expect to Have MAF Sensor Issues?
If you have driven your vehicle for 18,000 to 25,000 miles, you may expect to encounter this problem. It will also depend on the type and model of your car. For instance, MAF sensors in compact and small cars tend to clog quicker. That’s probably because of the small sizes of their engine bays.
All sorts of dirt and debris can easily settle in a small engine bay since there’s only a small space where dirt particles can move. Dirt, combustion debris, oil vapor flows, and other contaminants can easily rest and contaminate the MAF sensor.
How Long Does a MAF Sensor Last?
Mass air flow sensors do not have expiration dates. They do not belong to the car components that have mileage warranties. MAF sensors are not even included in the list of car components that need regular or preventive maintenance.
In practice, they can indefinitely continue to be in service as long as they work properly.
So can you drive with a bad mass air flow sensor? You can drive with a bad mass air flow sensor, but only for a very limited time. If you drive for too long with a bad mass air flow sensor, it can lead to serious engine problems.
Next, let’s look at how to troubleshoot a bad mass air flow sensor.
How to Troubleshoot a Bad Mass Air Flow Sensor
Leave the checking, repair, or replacement of a bad mass air flow sensor to the hands of a professional car mechanic. But it is well and good if you understand how to do it so that you will be able to take care of this sensitive device properly.
The typical troubleshooting of MAF sensors entails the following steps:
- Examine the connector and check if it has good contact and a correct fit.
- Next, check the MAF sensor if there is any damage.
- Examine the sensor’s measuring components for any damage.
- Switch on the ignition and check the voltage supply. Refer to the circuit diagram to see the pin assignment. The reference value is 7.5 to 14 volts.
- While the engine is running, check the output voltage. Refer to the circuit diagram to see the pin assignments. The reference value is 0 to 5 volts.
- Examine the connection cables between the sensor connector for transmission and the unplugged control unit connector. Refer to the circuit diagram if necessary. The reference value is approximately 0 ohm.
- Test the MAF sensor electronically by the engine management control unit. If a fault happens, search for the fault code. The control unit usually stores this code. You can get it by using a diagnostic unit.
You can check the MAF sensor’s frequency and voltage signal by connecting its voltage signal wire and ground wire to a voltmeter. Start the engine and read the voltmeter. On some sensors, the volt reading should be 2.5 volts.
What Is a Mass Air Flow Sensor?
To better appreciate what it does, you need to know what a mass air flow sensor is. This modern car component is also called the MAF sensor, the acronym for mass air flow. It is a device that determines the amount of air mass that passes through a car’s air intake.
With the help of the power control module or PCM, the MAF sensor calculates the amount of air flow by multiplying the air volume by the air density. The engine computer uses the MAF sensor signal to determine the amount of fuel that needs to be injected to meet the right air to fuel ratio.
The signal from the MAF sensor is used to determine the load on the car engine. This means that this sensor influences the functions of other systems in the car.
For instance, it can change the automatic shifting patterns in vehicles with automatic transmissions. It can also cause problems for the car’s traction system.
Because of these car components’ interdependencies, you need to look into other possibilities instead of just focusing your attention on a bad MAF sensor. A bad MAF sensor may cause your car to run too rich or too lean. It can cause your car to jerk when you are accelerating.
These are only some of the problems–there are many more. This sensor contributes to the efficient performance of your car. If it is malfunctioning, go and check it right away. It may only need some cleaning. Compared to repairing or replacing the engine, it is considerably less taxing on your wallet if it only needs replacement.
Types of Mass Air Flow Sensors
The MAF sensor in your car belongs to one of the four types of MAF sensors. The sensor your car is using most probably belongs to the most common type, which is the hot wire MAF sensor. This type of sensor has two wires. One of the wires is heated while the other is not.
In this type of sensor, the PCM calculates the amount of air going into the engine by the amount of current required to maintain the hot wire’s temperature at 200°F (93.33°C) hotter than the cold wire.
When there’s a difference in temperature between these two wires, the MAF sensor will either decrease or increase the current going to the heated wire. This results in the flow of more air or less air into the engine.
The other types of sensors are:
- Vane MAF Sensor – Also called airflow meter. It uses a potentiometer to transfer a signal or variable. In some cases, it uses a changing voltage signal to the PCM to measure air volume.
- Karman Vortex MAF Sensor – It’s similar to other sensors, but it also forms a vortex sensed by a photocoupler and a mirror. The signal is converted to power and sent to the PCM.
- Cold Wire MAF Sensor – Uses a thin metallic strip that vibrates as air passes through. The variations in the vibration frequencies are sent as a signal to the Engine Control Module (ECM).
Conclusion – Can You Drive with a Bad Mass Air Flow Sensor?
You can drive with a bad mass air flow sensor – but only for a short time. It is not advisable to drive long distances with a bad mass air flow sensor because it can lead to more serious car or truck problems. A faulty sensor issue can worsen and even lead to a more serious problem with the engine.