Skip the auto shop - Our mechanics make house calls

P0103 OBD-II Trouble Code: Mass Airflow (MAF) Circuit High Air Flow and High Voltage Output

check engine light logo

P0103 Trouble code definition

Mass Airflow (MAF) Circuit High Air Flow and High Voltage Output

  • The Code P0103 code is often associated with a P0100, P0101, P0102 and P0104 codes which are closely related.

What the P0103 code means

P0103 is the code for a problem with the Mass Airflow (MAF) Sensor having a high voltage output to the Engine Control Unit (ECU).

What causes the P0103 code?

The MAF Sensor high voltage output to the ECU may have several causes:

  • The source of the problem is the sensor voltage output is higher than normal or required by the ECU to function with other sensor signals.

  • The wiring or MAF sensor may be too close to higher voltage consumption components, alternators, ignition wires, etc. causing inaccurate output signals.

  • The air intake system from the air filter assembly may have a large leak like a bad vacuum hose, air intake hose, loose hose clamps or other intake leak before the MAF sensor.

  • MAF sensors must operate within specific ranges to send correct signals for the ECU to adjust correctly and in conjunction with other sensors for proper engine operation.

What are the symptoms of the P0103 code?

  • P0103 code will be normally preceded by the Check Engine Light coming on the dashboard display.

  • Generally, the vehicle runs well enough to drive. The engine often operates near normally but it may run slightly erratically, have less power, back fire and idle inconsistently higher than normal.

  • If the engine runs poorly, the situation requires attention as soon as possible or internal engine damage could occur.

How does a mechanic diagnose the P0103 code?

  • P0103 is diagnosed with a test with an OBD- II scanner. The OBD-II code should be reset and then road test the vehicle to see if the Check Engine Light and code comes back. He can observe this by watching it live on his scanner while driving. If the code comes back, then the mechanic will need to do a close visual inspection to determine if any electrical connector, wiring, sensor, air cleaner, intake or vacuum hoses, loose hose clamps, and MAF need repair or replacement.

  • If no problems are noted, then the next step is to have the mechanic do a circuit test with a multimeter that has a digital display to show sampling rate and sensor range readings to determine if the MAF sensor output is really too high.

Common mistakes when diagnosing the P0103 code

Diagnostic errors are largely due to not following the proper procedure:

  • First, follow the test procedure for inspecting the connector, wiring and sensor. Do not buy a MAF sensor unless the other tests indicate no problem.

  • Before buying a MAF sensor, try cleaning it with a specialized spray cleaner made for MAF sensors such as CRC 05110 as these often get considerable carbon build up from the emission system, especially at idle.

  • The air intake system may have very simple causes like loose clamps, air hoses or vacuum lines, so a close inspection is necessary before buying an expensive MAF unit.

How serious is the P0103 code?

  • The P0103 code generally will not prevent the car from driving unless the leak is massive.

  • Take the car to a qualified technician check it out as soon as possible.

  • The MAF sensor issue can cause excessive fuel consumption, smoking, rough operation and difficulty starting in certain circumstances. Continued driving could cause internal engine damage.

  • Often times, if the Check Engine Light came on immediately at start up, the OBD- II system can be reset and the vehicle will operate normally.

What repairs can fix the P0103 code?

The most common potential repairs for the P0103 code are as follows:

  • Recheck code with a scanner. Reset the fault codes and perform a road test.

  • If the P0103 code comes back, then follow the order of the test procedure.

  • Inspect the electrical connector to ensure it is attached correctly. Disconnect it and then reinstall to ensure fresh and positive electrical connection.

  • Carefully inspect for wiring being frayed, damaged or broken on the connector. Repair or replace as necessary before further testing.

  • Check for vacuum leaks, loose hoses, bad fittings, and clamps on the intake, especially on older cars. Old components can get hard and crack.

Additional comments for consideration regarding the P0103 code

Many vehicles with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train.

If the Check Engine Light comes on and the vehicle seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.

Need help with a P0103 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...
P0359 OBD-II Trouble Code: Ignition Coil I Primary/Secondary Circuit Malfunction
P0359 code definition The P0359 code indicates that a fault has been detected in one of the vehicle’s ignition coils, generally the number 9 coil. This code can also be associated...

Related questions

Q: Car vibrating and shaking with the smell coming from the muffler

The awful smell your referring to is probably the catalytic converter being damaged. When there is a severe misfire, like what you're describing, the catalytic converter will deteriorate, resulting in a sulfur smell. Of course, the misfire will also illuminate...

Q: P1743

This code is for a transmission overdrive solenoid problem. The overdrive solenoid would need to be tested to see if it has the proper resistance of 10 to 20 ohms. If it is okay then the harness will need to...

Q: Check engine light on, temperature goes to hot, noisy engine, car shuddring and turns off.

Fault codes need to be read out from the engine computer. There is a technical service bulletin (TSB) out by Lexus that points to a faulty thermostat causing a Check Engine Light, and that the thermostat should be replaced based...