P0103: Mass or Volume Air Flow Sensor A Circuit High
What to do
Expect a rich-running engine, possibly with visible exhaust smoke. Have it seen to promptly, as prolonged rich running damages the catalytic converter.
What this code means
The airflow signal is higher than the sensor should be able to report. The module responds by adding fuel to match air that is not really there, so the engine runs rich — black smoke, fouled plugs, and over time a catalytic converter working far harder than it should. An intake leak between the sensor and the throttle cannot cause this one; a wiring fault or a failed sensor usually can.
Likely causes
Start here
- Contaminated or failing mass air flow sensor · easy
- Wiring shorted to voltage · moderate
- Corroded or loose connector · easy
Less common
Rare
- Failed control module · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
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