Hyundai i40 P0102: Meaning, Causes, + How to Fix

MAF Sensor Low Voltage Input

If you own a Hyundai i40, you may have encountered the P0102 trouble code. This code indicates that the Mass Air Flow (MAF) circuit is low and not performing within its specified operating range. When this happens, your car may experience drivability issues such as stalling, lack of power, rough idle, and hesitation.

There are several potential causes of the P0102 code, including a faulty or contaminated MAF sensor, debris blocking the air flow sensor element, vacuum leaks, a poorly closed air filter box, or an incorrect air filter installed.

If you encounter this code, it is important to diagnose and fix the problem promptly to avoid further damage to your car.

Hyundai i40 P0102

The most common causes of the P0102 code are related to the MAF sensor itself or the connection to it. However, it’s not uncommon to deal with some sort of leak or electrical short as well.

P0102 Code Meaning and Definition


P0102: MAF Sensor – Circuit Low Voltage Input

MAF Sensor

A typical MAF Sensor

Your i40’s MAF sensor is responsible for metering the air as it enters the engine. The PCM (Powertrain Control Module) uses this data to adjust the air fuel mixture. The MAF is one of the most important sensors your i40 has.

Circuit Low

When the MAF circuit is low, it means that the sensor is not performing within its specified operating range. Specifically, the voltage value is lower than the expected range.

This can cause a variety of issues, including reduced fuel economy, trouble starting the engine, and poor engine performance.

To diagnose and fix this issue, you will need to start by checking the possible causes listed below. This may involve cleaning or replacing your i40’s MAF sensor, checking for air leaks, or repairing any electrical shorts.

If you are unsure how to proceed, it’s always best to take your Hyundai i40 to a qualified mechanic who can diagnose and fix the issue for you. Ignoring the P0102 code can lead to more serious engine problems down the line, so it’s important to address it as soon as possible.


If your Hyundai i40 is experiencing a P0102 trouble code, you may notice a variety of symptoms. Here are some of the most common symptoms associated with a P0102 code:

  • Check Engine Light: The most obvious sign of a P0102 code is the illumination of the Check Engine Light on your car’s dashboard. This light will come on to indicate that there is a problem with your vehicle’s emissions system.
  • Rough Idle: If your i40 is idling roughly, it may be a sign that there is an issue with the mass air flow (MAF) sensor. A dirty or faulty MAF sensor can cause the engine to run poorly at idle.
  • Hesitation: Another symptom of a faulty MAF sensor is hesitation or stumbling during acceleration. You may notice that your i40 is not as responsive as it used to be or that it takes longer to accelerate than it should.
  • Stalling: In some cases, a P0102 code can cause your i40 to stall or even refuse to start. This is because the MAF sensor is responsible for measuring the amount of air entering the engine, and if it is not functioning properly, the engine may not receive enough air to run.
  • Reduced Fuel Efficiency: A faulty MAF sensor can also cause your i40 to use more fuel than it normally would. This is because the engine is not receiving the correct amount of air, which can lead to an improper air/fuel mixture and reduced fuel efficiency.


If you are experiencing the P0102 code in your Hyundai i40, there are a few potential causes to consider. Here are some of the most common causes of the P0102 code:

P0101 Causes Hyundai i40
  • Dirty air filter: A dirty air filter can cause the MAF sensor to read incorrect values, leading to the P0102 code.
  • Dirty MAF sensor: Over time, the MAF sensor can become dirty or contaminated, which can cause it to fail or read incorrect values.
  • Intake air leaks: Leaks in the intake system can cause the MAF sensor to read incorrect values, leading to the P0102 code.
  • Faulty MAF sensor: If the MAF sensor itself is faulty, it may need to be replaced.
  • Open or shorted MAF sensor harness: A problem with the wiring or connection to the MAF sensor can cause the P0102 code to appear.
  • Loose terminals in the MAF sensor connector: This is a known issue with some Hyundai i40 models, where loose terminals in the MAF sensor connector can cause the P0102 code to appear.

Hyundai i40 P0102 Diagnosis

Here are some steps you can take to diagnose P0102 in your Hyundai i40.

  1. Check the air filter: A dirty air filter can restrict airflow and cause the MAF sensor to give a low input reading. Make sure the air filter is clean and not clogged.
  2. Inspect the MAF sensor: The MAF sensor may be dirty or faulty. Inspect the sensor and clean it if necessary. If cleaning doesn’t work, you may need to replace the sensor.
  3. Check for air leaks: Air leaks in the intake system can cause the MAF sensor to give a low input reading. Inspect the intake system for any leaks or cracks and repair them as necessary.
  4. Check the wiring and connections: The wiring and connections to the MAF sensor may be damaged or loose. Inspect them and repair or replace as necessary.
  5. Use a diagnostic scanner: If you are unable to diagnose the issue on your own, you can use a diagnostic scanner to read the trouble codes and pinpoint the problem. Use any codes that came up with P0102 in order to

Remember that the P0102 code may not always be the cause of your i40’s performance issues. It’s important to perform a thorough diagnosis to identify any other potential issues that may be contributing to the problem.


If you have determined that your Hyundai i40 has a P0102 code, there are a few steps you can take to repair the issue. Here are some options:

  • Clean the Mass Air Flow (MAF) Sensor: A dirty MAF sensor can cause the P0102 code to appear. You can clean the sensor with low compressed air or MAF sensor cleaner. Be sure to follow the manufacturer’s instructions carefully.

  • Replace the Air Filter: A clogged or dirty air filter can also cause the P0102 code. Replace the air filter if it is dirty and see if the code disappears.

  • Replace the MAF Sensor: If cleaning the sensor or replacing the air filter does not work, you may need to replace the MAF sensor. This is a more expensive option, but it may be necessary if the sensor is faulty.

It is important to note that if you replace the MAF sensor, you should use an OEM Hyundai (original equipment manufacturer) part. Aftermarket parts may not work as well and could cause additional issues.

If you are uncomfortable with performing any of these repairs yourself, it is best to take your vehicle to a certified mechanic. They can diagnose and repair the issue for you.

Remember, it is important to address the P0102 code as soon as possible. Ignoring the issue could lead to further damage to your vehicle and could cause more expensive repairs down the line.