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P0100 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


Error code P0100 denotes an issue with the circuit between the powertrain control module (PCM, aka electronic control module or ECM) and the Mass Air Flow (MAF) sensor. This error can come from a faulty connection or an issue with the sensor itself.


P0100 is a trouble code for a MAF circuit malfunction. When the PCM detects a signal that deviates from the normal range, or disappears for a period of time, it registers this code.

There are several issues anywhere between the MAF sensor and the PCM that can potentially cause a P0100 code. A certified mechanic will need to diagnose the problem with an OBD-II scan and an inspection along the circuit.

Certain makes and models are more prone to registering a P0100. Nissans (particularly Frontiers), Toyotas, Fords, Chevrolets, Subarus and Kias are commonly susceptible to malfunctions with the MAF sensor.


Causes of a P0100 code can occur with the MAF sensor, the connection or with the PCM. The most common source of trouble occurs with the connection and wiring. Terminals may have loose connections or there may be corrosion or damage to the wiring. Other possible causes can include the following:

  • Obstructed airflow from clogged filters or intake.
  • Faulty, damaged or dirty MAF sensor.
  • Vacuum leaks.
  • PCM malfunction.

Also read: 6 Easy Steps On How To Clean A Car Air Filter


The vehicle will run with a P0100 trouble code, but it will normally suffer from driveability issues until it is resolved. The Check Engine light will be the first indication of an issue. It is common to face the following symptoms of a P0100 code:

  • Erratic engine power, even while idling.
  • Stalling and poor acceleration.
  • Rough engine performance.
  • Difficulty starting.


Mechanics use an OBD-II scanner to confirm the code. They then reset the codes and test drive the vehicle, monitoring for the same error code with their scanner. If it registers the code again, they perform a visual inspection on the MAF, the PCM and the wirings and connections. They will also check for leaks, obstructions or damage to the air duct and filter.

Common mistakes

The most common mistake in handling a P0100 code is not following the proper testing process. Many people are quick to replace the MAF sensor as soon as the code pops up. If the problem is actually related to something outside the sensor, like the connectors or PCM, you may spend money needlessly on a new sensor. Furthermore, faulty MAF sensors may just need cleaning or repair, rather than replacement.

It is crucial to follow the testing steps to accurately diagnose and fix the problem. Before buying a new MAF sensor, attempt to clean it with a special cleaner available at most auto parts stores.

How serious is this?

While the car may still run and show minor symptoms, it is best to have a mechanic diagnose and resolve the issue at the first possible opportunity. Along with performance problems, vehicles registering a P0100 code often experience lower fuel efficiency.

In many instances, if the Check Engine light illuminates when you start the car, a reset of the OBD-II system can resolve the issue.

What repairs can fix the code?

repair manuals

The first step is having the technician perform diagnostics, a system reset and a road test.

Inspect the electrical connections to ensure there is no damage or loose attachments. Connectors should be detached and reinstalled to refresh the connection. If any wiring is corroded, frayed or broken, it needs to be repaired or replaced.

Use a voltmeter to check the MAF sensor signal. The vehicle’s manual will provide a reference chart for proper values to compare against the readings.

Clean contaminated sensors and replace the MAF if needed.

Related codes

The P0100 code refers to an MAF circuit malfunction. Related codes: P0101, P0102, P0103 and P0104 detail issues within the circuit, such as its performance and whether its signal is too low or high relative to the expected range.


A car registering a P0100 code may not have any symptoms other than a Check Engine light. No matter how the drivability is affected, the issue needs immediate diagnosis and correction to ensure optimal performance. Always refer to your vehicle’s manual when attempting a DIY fix. For the most effective solution, follow up with a certified mechanic as soon as possible.

P0100 Code – What Does It Mean & How To Fix It