P0101 — Mass Air Flow Sensor Range/Performance

P0101 means the mass air flow sensor is reporting an airflow value that doesn't match what the engine computer expects. Usually a dirty MAF sensor or an unmetered air leak after the sensor.

Cost range: $20–$400. Severity: medium. Safe to drive? Usually yes, short trips. Expect hesitation and poor fuel economy until it's fixed.

Most common causes of P0101

  1. Contaminated MAF sensor element — Oil from an over-oiled aftermarket air filter is the classic culprit. Cleaning with MAF-specific spray often fixes it outright. ($15–$30)
  2. Air leak between MAF and throttle body — A split intake boot lets in air the sensor never counted. ($50–$200)
  3. Clogged or collapsed air filter — Restricts airflow enough to push readings out of range. ($20–$60)
  4. Failed MAF sensor — Replace only after cleaning and leak-checking. ($150–$400)

Symptoms drivers report with P0101