Warning! Pay Attention to These Bad MAF Sensor Symptoms

What’s the function of the mass airflow (MAF) sensor in a car? Well, it plays a vital role in helping an automobile maintain its fuel-air ratio. It gauges the volume of air entering the engine and sends that information to the Engine Control Unit (ECU). Based on that piece of information, the ECU determines the amount of gas that fuel injectors need to send to each of the cylinders. You should be careful about bad MAF sensor symptoms because a little malfunction in this device leads to poor engine performance.

3 Most Common Bad MAF Sensor Symptoms

An MAF sensor needs to run properly because the ECU needs information about the amount of air in the engine. Fortunately, detecting bad MAF sensor symptoms is not rocket science. Just be alert for these common symptoms:

1. The car runs rich at idling or lean when running

The Hot-wire MAF sensor is the most commonly used sensor. Contamination of the wire will insulate it and will not allow it to work properly; hence, it will send inaccurate information to the car’s computer. As a result, the engine will run rich at idle and lean when it is running. A change in fuel economy is the only way to detect that there are some problems with the hot wire.

symptom of bad mass air flow sensor
You have to clean the MAF if it’s dirty (Photo: Shutterstock)

If the wire is just dirty, caused by dirt from the oil or spider webs, cleaning it will solve the issue.

2. Engine continuously runs rich or lean

It’s another common symptom of bad mass airflow sensor and it happens when the wire is deformed or there is damage to the device’s electrical components. The engine runs rich or lean because the sensor frequently sends reports that are either higher or lower than the actual airflow. There is no solution for a damaged sensor but to replace it. The same glitch can be the outcome of an issue with the engine control system. So, diagnose it if the MAF sensor turns out to be fine.

In fact, it is hard to detect this symptom of bad mass airflow sensor when the control system runs smoothly. You have to look into a change in the mileage to spot this issue.

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3. Engine idles roughly or halts

These are the bad MAF sensor symptoms that indicate that the sensor is completely out of order. In that case, the car’s computer cannot control the fuel-to-air ratio because the sensor does not send any information to it. As a result, the engine either halts or idles roughly. Replacing the MAF sensor is the only solution to this complication.

bad maf sensor symptoms
The engine will stop when the sensor fails. (Photo: Shutterstock)

4. Check engine light on

One of the most obvious symptoms, when an MAF sensor is going bad, is that the check engine light will be on your car dashboard. As soon as this sensor fails, other sensors mounted around the engine will immediately detect and send an alarm signal to an ECU. From there, notify the driver through the Check Engine light. Therefore, drivers need to regularly pay attention to the signal on the car dashboard to detect and fix the problem timely. 

5. Fuel consumption

When you notice your car consumes fuel abnormally and black smoke from the exhaust, it’s also one of the MAF sensor symptoms. A bad sensor will cause the measurement data to be erroneous, the ECU calculates incorrectly, causing more fuel injection into the combustion chamber than usual, causing fuel consumption. In addition, the excess gasoline is not fully burned, which is the reason why the exhaust pipe produces black smoke.

What Are The Causes Of A Bad MAF Sensor?

After understanding mass air flow sensor symptoms, we should know about the culprits behind this problem: A faulty MAF sensor can come from several reasons. In particular, the sensor is stuck with too much dirt or grease which is the main cause that causes the ECU to misinterpret the input signals. In addition, this sensor is also affected by the high temperature of the engine for a long time without being replaced, which also easily leads to the wrong analysis of the mass airflow. Besides, If the air filter is not maintained, lubricated, and replaced periodically, causing many impurities to leak into your engine will directly affect the quality of the air mixture. Better yet, drivers need to regularly check and maintain the air filter and especially the MAF sensor at a trusted mechanic to detect damage and have timely solutions.

How to tell if your Mass Air Flow Sensor is bad? Let’s check out the video below:

How to Clean an MAF Sensor?

When the sensor is just dirty, cleaning it up will bring order into a disruptive engine system. You can do it yourself by opening the car’s airbox and removing the sensor. Clean it with rubbing alcohol MAF sensor cleaner. Put it back into its place when it is completely dry. Be careful not to damage the wires when removing and reinstalling the sensor.

In some cases, an MAF sensor is beyond repair, at that time cleaning this sensor is no use so you need to replace the MAF sensor with a new one. The driver should perform the replacement steps in the sequence below. 

Step 1: Turn off the ignition switch and disconnect the battery to avoid danger in the process.

Step 2: Remove the connector by pressing firmly on the plastic lever next to the sensor, using a screwdriver to remove the surrounding screws.

Step 3: Replace the old sensor with the new sensor.

Step 4: Reattach the sensor, and battery connections and turn on the ignition switch.

Step 5: Reset ECU data with the OBD code reader and try to start the car again.

When you notice any symptoms of a bad MAF sensor, the best way we want to recommend is replacing it instead of repairing or cleaning this sensor. And it doesn’t cost too much for you to buy a new MAF sensor.