What does a MAF sensor do on a diesel?

Asked By: Benicia Chowdhury | Last Updated: 1st June, 2020
Category: automotive auto parts
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WHAT IS A MASS AIR FLOW SENSOR? MAF sensors essentially measure the amount of air that flows into the engine to help create an optimal air-to-fuel ratio, this allows the vehicle to perform at its full potential and operate efficiently.

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Similarly, it is asked, what are the signs of a bad mass airflow sensor?

Here are some of the most common symptoms of a faulty mass airflow sensor:

  • The engine is very hard to start or turn over.
  • The engine stalls shortly after starting.
  • The engine hesitates or drags while under load or idle.
  • Hesitation and jerking during acceleration.
  • The engine hiccups.
  • Excessively rich or lean idling.

One may also ask, do diesel engines have mass air flow sensors? Diesel engines do not require mass air sensors. they do not require it, but some have them.

Keeping this in view, what happens when the MAF sensor goes bad?

Symptoms of a bad mass air flow sensor As a result, a bad mass air flow sensor causes various driveability problems, including a no-start, stalling, lack of power and poor acceleration. In addition, a faulty mass air flow sensor might cause the Check Engine or Service Engine Soon light to come on.

Will my car run if I unplug the MAF sensor?

Well, the answer to that is no. If you disconnect the mass airflow sensor, then the car should keep running and still be able to start normally. This means that if your mass airflow sensor dies completely, then your car will stay running and surprisingly the car might run better without the mass airflow sensor.

32 Related Question Answers Found

Will a bad MAF throw a code?

If a fault code or some other symptom shows up only on one bank, the MAF is probably OK. A dirty MAF can be diagnosed quickly and accurately with a scan tool running in generic OBD II mode. During a full-throttle acceleration, the O2 sensor would normally indicate rich A/F ratio, but it won't if the MAF is dirty.

Why would a car run better with the mass air flow sensor unplugged?

Because either the sensor is reporting incorrect air amount and or air temperature to the ECU. By disconnecting the sensor the ECU switches to limp mode and the car may idle better . Some MAF sensor wires can be cleaned and some cannot as the wires are not easily accessible .

Can you drive with a bad mass air flow sensor?

You can drive your vehicle with a bad mass air flow sensor for a while, but it is not advisable to continue doing so for a long time even if your car can still run and that is because, Ignoring your car MAF sensor problem can escalate beyond just the Mass air flow sensor problem to a more severe engine problem that

Will a car run without mass air flow sensor?

While the vehicle may run with a dirty or broken MAF, it will not be efficient and may cause mechanical damage to the engine due to running in a lean condition. A failed MAF sensor may not send any airflow information to the PCM. A dirty MAF will give symptoms of rich at idle and/or lean under a load.

Can a mass air flow sensor mess up your transmission?


A bad MAF can cause hard or incorrect shifts. As far as I know, it will not put the transmission into limp mode; that's triggered by problems detected with the transmission. It sure as heck won't make it leak fluid. OTOH, low fluid will certainly cause all sorts of transmission trouble.

How much does it cost to replace a mass air flow sensor?

To get your mass air flow sensor replaced, you will pay about $300, on average. The labor should cost you around $60, while parts are about $240. The prices vary based on where you go for servicing and what kind of car you have.

How long do mass air flow sensors last?

Mass airflow sensors (MAF) have no expiration date. They are not included on the manufacturer's scheduled maintenance list of things to replace based on mileage, like spark plugs or filters. They can remain in service indefinitely as long as they continue to function correctly.

Can you clean a MAF sensor?

We recommend that you clean the MAF sensor every time you change your air filter. Spray 10 to 15 spurts of the mass air flower cleaner onto the wire or plate. Don't scrub the parts; you may break the wire or damage the plate. Allow the MAF sensor to dry completely before reinstalling it in the air duct.

How do you fix a mass air flow sensor?

How to Repair a Mass Air Flow Sensor
  1. Open the hood of your vehicle and locate the mass air flow sensor on or near the larger air cleaner box.
  2. Remove the the two screws that hold the mass air flow sensor to the intake system.
  3. Pull the mass air flow sensor out of the intake.

Can a bad mass air flow sensor cause misfire?


Even a dirty MAF sensor can cause a lean code and/or misfire to occur. The engine may be stalling because it isn't getting enough throttle opening. The cause is often a problem in the idle air control system. The first thing to check is the intake vacuum with a vacuum gauge.

What type of sensor is a MAF sensor?

A mass (air) flow sensor (MAF) is a sensor used to determine the mass flow rate of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine.

How do you test a mass air flow sensor with a scan tool?

Connect a scan tool to see the MAF sensor Parameter Identification Data (PID) information. With the engine at idle, the MAF's PID value should read anywhere from 2 to 7 grams/second (g/s) at idle and rise to between 15 to 25 g/s at 2500 rpm, depending on engine size.

Can a bad mass air flow sensor cause rough idle?

A faulty mass airflow sensor will send wrong airflow information to your engine's computer that can cause rough idle or stalling out.

Does MAF sensor affect Turbo?

Yes. If the MAF is faulty, the engine computer may be unsure how to properly control the turbo- this is more applicable in a variable vane turbo than a wastegate, but can still apply. The issue may be cured with a new sensor, but if run that way for a long time, possible vane fouling can occur.

What is a normal reading for a mass air flow sensor?


Mass air flow sensors typically either send a voltage, or frequency signal to the powertrain control module (PCM). Hot wire sensors typically have an operating range of 0 - 5 volts, with idle voltage being around . 5 - . 8 volts and full throttle application is normally between 4 and 5 volts.

How do you bypass a MAF sensor?

How to Bypass the Cold Air Intake Sensor
  1. Turn off the ignition of your vehicle and open its hood.
  2. Disconnect the negative battery cable (red). Locate the mass air flow (MAF) sensor on the air intake.
  3. Grasp the wire harness that connects the MAF sensor to the power unit in the engine compartment and gently pull it out of the MAF sensor.

Do all cars have MAF sensors?

Most of today's cars use the Hot Wire MAF. What are some differences between a MAP and MAF sensor? While a MAF sensor is always located before the throttle body, a MAP sensor can usually be found attached to the intake manifold. In cases like this, there is a MAF sensor as well.