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  • The P0103 code stands for “Mass or Volume Air Flow (MAF) ‘A’ Circuit High,” which means the powertrain control module (PCM) detected a high voltage output coming from the MAF sensor.
  • Some of the possible causes of the P0103 code include a faulty MAF, an issue with the MAF’s circuit, and PCM problems.
  • An illuminated malfunction indicator lamp (MIL), black smoke from the tailpipe, and hard starting are some common symptoms related to the P0103 code.

The P0103 code indicates that your car’s computer perceives a problem with the mass air flow (MAF) sensor or its circuit. What signs do you need to look out for and how should you deal with this specific trouble code? Find out the answers to these questions and more with this short guide.

What Does the P0103 Code Mean?

Diagnostic trouble code (DTC) P0103 stands for “Mass or Volume Air Flow “A” Circuit High.”

As mentioned above, the MAF sensor is responsible for measuring the amount of air entering your vehicle’s engine. Most MAF sensors contain a wire (or in some cases, a grid) that’s exposed to the intake airflow. Your vehicle’s primary computer, often called the powertrain control module or PCM, applies a specific voltage to this wire to heat it to a certain temperature. The intake air cools the heated wire and changes its resistance.

The PCM changes the voltage it applies to the wire in response to the change in the wire’s resistance. Note that the voltage level that gets sent back to the PCM is proportional to the air flowing through the sensor.

See also  P0102 Code: Mass Air Flow (MAF) Circuit Low

The PCM uses the information from this sensor to monitor the intake air volume. It also uses the data coming from the MAF sensor to decide the correct amount of fuel and even the ignition timing, in some cases.

DTC P0103 registers in your vehicle’s memory when the PCM detects a high voltage output coming from the MAF sensor. When this trouble code is set, the PCM may enter into a failsafe mode in some vehicles to prevent serious damage to your engine and the rest of the vehicle. The failsafe mode will be lifted once the underlying issues are addressed.

If you wish to fix code P0103 yourself, you can read our in-depth discussion about mass air flow for more useful information.

mass air flow sensor
DTC P0103 registers in your vehicle’s memory when the PCM detects a high voltage output coming from the MAF sensor.

Note: The definition of code p0103 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition. 

What are the Possible Causes of the P0103 Code?

There are a few possible reasons why the P0103 code is set. Below are some of the most likely causes that bring about this trouble code:

  • Faulty MAF
  • An issue with the MAF’s circuit
  • A problem with the PCM, such as software in need of an update

It’s important to note that there is a certain window the ECM/PCM will accept as normal. If the signal coming from the MAF sensor drops below that acceptable window, a code is set. Again, the code is different from one manufacturer to the next, so you may get a different code on your vehicle that means the same thing code P0103 does.

It’s important to note that there is a certain window the ECM/PCM will accept as normal. If the signal coming from the MAF sensor drops below that acceptable window, a code is set.

 Richard McCuistian, ASE Certified Master Automobile Technician

What are the Common Symptoms of the P0103 Code?

Like most OBD-II codes, the P0103 code has a handful of symptoms. To better understand the root cause of the issue, it’s good to observe your vehicle if it exhibits any one or a combination of the following signs:

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black smoke from tailpipe
Black smoke coming from the tailpipe is a sign that you may be dealing with the P0103 code.
  • Malfunction indicator lamp (MIL) or check engine light is illuminated
  • Engine runs rough
  • Black smoke is coming from the tailpipe
  • Engine is stalling
  • Engine is hard to start or stalls after it starts
  • Other driveability symptoms are present
  • In some cases, this error code might not even exhibit any noticeable symptoms

How to Diagnose the P0103 Code

Diagnosing any OBD-II code can be quite a challenge since there are a handful of possible causes and the symptoms might not even point to a specific cause. However, this doesn’t mean that this procedure is impossible.

You’ll need to rely on accurate and easy-to-access information so that you can troubleshoot and repair your vehicle effectively. Repair manuals and subscriptions are a good way to start because they provide detailed instructions and clear diagrams.

If you want to know more about the P0103 code and how to troubleshoot it, you can use the online video resources below to get an idea of what the process might involve:

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How to Fix the P0103 Code

An effective P0103 code fix relies on an accurate and thorough diagnosis. Note that repair and diagnosis steps will vary depending on the vehicle’s make and model, as vehicles are configured differently. Because of this, you have to make sure that you get proper repair information that’s suited to your specific vehicle.

Repair guides, manuals, and subscriptions can be helpful to the seasoned DIYer. However, if you’re starting out, it’s best to consult a professional mechanic or technician before making any changes to your vehicle.

Other Notes About P0103

Compared to other OBD-II codes, the P0103 code is quite rare, although it is often associated with other MAF sensor-related trouble codes such as P0100, P0101, P0102, and P0104. In fact, both P0103 and P0102 cause some vehicles to go into failsafe mode.

If you’re dealing with the P0103 code, you also might encounter other trouble codes along with it such as misfire codes or oxygen (O2) sensor codes. In any case, you should get a professional’s help if you don’t know how to deal with this code.

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About The Authors
Written By Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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