Fault code P0104 – mass or volume air flow (MAF/VAF) “A” circuit intermittent/erratic

Fault code P0104 is called “Mass or Volume Air Flow (MAF/VAF) “A” Circuit Intermittent/Erratic” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P0104

This Diagnostic Trouble Code (DTC) is a generic powertrain code. Error P0104 is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

Fault code P0104 – mass or volume air flow (MAF/VAF)

The mass air flow sensor (MAF) is a sensor installed in the air intake duct of the vehicle engine, after the air filter. It is used to measure the volume and density of the air drawn into the engine. The mass air flow sensor itself measures only a portion of the incoming air. This value is used to calculate the total volume and density of the intake air.

The Powertrain Control Module (PCM) uses this reading along with other sensor parameters. To ensure proper fuel delivery at all times, for optimum power and fuel economy.

Typically, this diagnostic trouble code (DTC) P0104 means that an intermittent or unstable fault has been detected in the “A” sensor or the mass or volume airflow circuit (MAF/VAF). The PCM detects that the actual frequency signal of the mass or volume flow sensor is not within the specified expected range of the calculated value.

Some mass airflow sensors also include an air temperature sensor. Which provides another value that the PCM uses for optimum engine performance.

Closely related MAF/VAF circuit fault codes include:

  • P0100 Mass or Volume Air Flow “A” Circuit Malfunction
  • P0101 Mass or Volume Air Flow “A” Circuit Range/Performance
  • P0102 Mass or Volume Air Flow “A” Circuit Low
  • P0103 Mass or Volume Air Flow “A” Circuit High

Symptoms of vehicle malfunctions

The main signal that an error P0104 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Check engine light on the control panel is on.
  2. Jerking / ignition skips.
  3. Black smoke coming out of the exhaust pipe.
  4. Engine stalls or fails to start.
  5. Loss of power.
  6. Lambda probe related errors are generated.

Factors that can cause this error code

The error code P0104 can mean that one or more of the following problems have occurred:

  • Mass or volumetric air flow sensor (MAF/VAF) may be dirty.
  • Defective mass air flow sensor.
  • Leaking intake air.
  • Electrical harness or connectors to the mass flow or volume flow sensor (MAF/VAF) may be worn (open, short-circuited, chafed, bad connection, etc.).
  • The fuel vapor purge valve from the tank is damaged and is introducing extra air into the intake port.
  • Worn or damaged gasket under throttle valve or intake manifold.
  • Worn vacuum lines.
  • Clogged catalytic converter (on some models).

Please note, there may be other fault codes along with error P0104. You may have ignition misfire codes or O₂ sensor codes. Therefore, it is important to get the “big picture” of how the systems work together and affect each other when diagnosing.

How to fix or reset OBD-2 code P0104

Some suggested steps for troubleshooting and fix the error code P0104:

  1. Check all cables and associated connectors leading to the mass or volume flow sensor (MAF/VAF). Make sure they are not broken or frayed. Repair or replace if necessary.
  2. Check for air leaks in the intake system. If found, repair the problem.
  3. Inspect the mass or volumetric air flow sensor (MAF/VAF) supply wire for dirt and dust.
  4. If the air filter is dirty, replace it.
  5. There are air intake systems with a grid, in which case you need to make sure it is clean.
  6. This code may be caused by a high resistance in the ground circuit of the absolute pressure sensor (MAP).
  7. Replace the mass air flow sensor.

Diagnose and repair of problems

Starting the diagnosis of the P0104 malfunction, check all the wiring as well as the connectors of the mass air flow sensor. Make sure they are intact, not frayed or broken. The wiring should not be too close to the wires / ignition coils, relays, etc.

Visually check for obvious air leaks in the air intake system. Also lack of vacuum on the MAP sensor can cause this fault code. It’s worth checking the air filter, if it’s dirty, it needs to be replaced. If there is a screen in the air intake system, make sure it is clean.

Carefully inspect the mass air flow sensor to see impurities such as dirt, dust, oil, etc. Clean thoroughly with MAF cleaning spray, this is usually a good diagnostic/repair step done on your own.

Low minimum air flow through the sensor port can cause this fault code to set at idle or during deceleration. Check for vacuum leaks after the mass air flow sensor.

Use a diagnostic tool to monitor the mass air flow sensor values, in real time. Check the Technical Service Bulletins (TSB) for your specific make/model for known problems with your vehicle.

Atmospheric pressure (BARO), which is used to calculate the predicted MAF value, is initially based on the MAP sensor when the key is on. High resistance in the MAP sensor ground circuit can cause this trouble code to set.

Perform an exhaust backpressure test to determine if the catalytic converter is clogged.

If you do need to replace the mass air flow sensor. It is recommended that you use the original OEM sensor from the manufacturer. Not to buy replacement parts of dubious origin.

Using a reusable oil air filter can cause a P0104 error code if it is overly lubricated. Oil can get on the thin wire and create a film inside the mass airflow sensor or contaminate it. Use something like MAF/VAF sensor spray to clean in these situations.

On which vehicles does this problem occur most frequently

Fault code P0104 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • Chevrolet
  • Citroen (Berlingo, C4, Picasso)
  • Dodge (Dakota)
  • Fiat (Ducato)
  • Ford (F-150, Focus)
  • Honda
  • Iveco
  • Jeep
  • Kia
  • Mazda (3, 6)
  • Mercedes-Benz
  • Nissan
  • Opel (Astra)
  • Peugeot (307)
  • Subaru
  • Toyota (Camry)
  • Volkswagen (Crafter, Passat)
  • LADA (Granta)

Fault code P0104 can sometimes be found with other errors. The most common are the following: P0113, P0420, P0605, B1352.

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