P0102 – Mass Air Flow (MAF) Circuit Low Input

Your scan tool throws the P0102 code?

Here is a quick brief to let you know what you’re facing and what to expect.

  • P0102 definition: Mass Air Flow (MAF) Circuit Low Input.
  • Code type: Generic – P0102 indicates the same problem whether you’re having a Chevy, Ford, or Nissan, etc.
  • Can I drive with the P0102 code? Yes, but extended driving can lead to costly repairs. 
  • Easy to fix? Beginner to intermediate DIY level.
  • Cost: $30 to $380. 

Keep driving with this code is not that dangerous. But the best way to avoid unnecessary expenses is to get it fixed ASAP.

Now let us take a deeper look into the code!


Table Of Contents


What Does The P0102 Code Mean?

The error P0102 code is triggered when the Mass Air Flow (MAF) sensor’s voltage is lower than 0.2v for a certain period of time. This number is telling the car’s computer that the amount of intake air is abnormally low. 

How Does The MAF Sensor Work?

The MAF sensor measures how much air is coming into the combustion chamber. Using this data, the computer can determine how much fuel is needed.

A typical MAF sensor has a sensing wire. This wire heats up during operation and is further cooled by the airflow. The cooling initiates a decrease in resistance leading to an increase in voltage. 

Therefore, the more air is coming, the higher the MAF’s output voltage. The number usually ranges from 0.5v to 5v. 

What Happens When The MAF Sensor’s Output Voltage Is Lower Than 0.2v?

The MAF sensor’s voltage being lower than 0.2v is telling the computer that there is little to no air entering the engine.

Of course, the computer does not believe in this number as it knows it’s an irrational number. 

So, what data does the computer take to adjust the air-fuel mixture

The answer is O2 sensors!

The problem is that O2 sensors are located after where the combustion takes place. For that reason, there is a delay in the air-fuel ratio adjustment. As the result, your car can run just fine when cruising but it will hesitate when you suddenly accelerate.  

Other codes related to the P0102 code are P0100 and P0101.

P0102 causes, symptoms and fixes

P0102: Causes, Symptoms, And How To Fix

Symptoms

Here are some common symptoms of P0102 that you should look out for:

  • Check engine light on
  • Hard starts
  • Engine stalling
  • Rough idle
  • Hesitate when accelerating

Causes

Cause #1: Dirty Air Filter

The accumulation of dirt in your air filter will restrict airflow. Therefore, the MAF reports there is not enough air coming. 

If this is your problem, your car can’t start (because there is actually no air for combustion.)

P0102 caused by a dirty air filter should be resolved by cleaning out the clogged air filter. This is an easy task and you can totally do it by yourself. 

Cause #2: Faulty MAF Sensor

When the sensing wire inside the MAF gets dirty, airflow can not cool it down properly. This leads to the MAF’s voltage drop and it underreports the intake air mass. 

The decision to replace your MAF sensor should be taken after a proper diagnosis.

Cause #3: MAF Sensor Wiring Harness Problems

Damaged MAF sensor wiring harness can contribute to your P0102 error code. The wiring could also be near components that consume higher voltage, such as alternators, ignition wires, etc. These could lead to false voltage readings as well.

Cause #4: PCM Issues (rare)

Finally, the Powertrain Control Module (PCM) will rarely be the source of your error code. A faulty PCM causes the vehicle to require multiple attempts before starting up. It may also result in the engine’s failure to start.

Replacing PCM should fix the problem. Installing this module will take about half an hour and require professional assistance to ensure proper operations.


P0102 Causes Identification: How to Diagnose

Following the recommended diagnostics process is the first step in resolving the P0102 code.

Diagnose Air Filter

First, open the hood and inspect the air filter to confirm if it is clogged or contaminated with debris. If it is the case, have your air filter cleaned with recommended cleaners.

Alternatively, when the air filter gets severely damaged, replacing it is the best option.

Diagnose MAF Sensor

After making sure that the air filter is clean, the MAF sensor is your next target.

The sensor is located between the air filter and the intake manifold. While the car is idling, unplug the MAF sensor, and the car should stall.

If it doesn’t, the MAF need to be cleaned or replaced.

As a motorhead, you must be familiar with the name Scotty Kilmer. He is famous for his DIY videos on car stuff. Let’s find out how this man replaced the MAF sensor properly!

Diagnose MAF Sensor Wiring Harness

Now, ensure you check the wiring of your MAF sensor thoroughly to inspect any broken, loose, frayed, or pinched cables and connections. Verify that the wiring harness is perfectly coupled to the MAF sensor.

Diagnose PCM

After eliminating all of the above possibilities, the last thing you should check is the PCM.

Up to this point, I recommend you have a mechanic inspect the PCM. This is a complicated and expensive process.

But don’t worry, this is a very rare case.


How Much Does It Cost To Fix The Code P0102?

Most of the time, replacing the MAF sensor will fix P0102. This is an easy fix and costs you about $30 to $150 to buy a new sensor.

The Estimated Repair Cost Of P0102

SolutionsRepair Cost
Replace faulty MAF sensorDIY: $30 to $150
Mechanic: $80 to $380
Clean dirty air filterDIY: a few bucks
Mechanic: $15 to $85
Replace PCMDIY: not recommended
Mechanic: $1,000 to $3,000

Note: The data in this table was collected in June 2022. The actual price depends on many factors, such as your car’s make and year, mechanic’s rate, etc.


You Ask, I Answer

The P0102 code is not as serious as you worry, but ignoring it could lead to further damages that cost an arm and a leg to repair.

Share your story with us if you have encountered the P0102 code and fixed it before.

Also, if you have any other questions related to this error code, feel free to leave a comment below, I’ll answer them all!

See ya!