DTC P0103: Mass Airflow (MAF) Sensor: Condition

1999 Mazda 626 ES, 2.5 D, StandardSECTION Condition

DTC P0103 indicates MAF signal was greater than 4.35 volts sometime during normal engine operation. Possible causes for this fault are as follows:

  • Restricted MAF sensor screen.
  • MAF SIG circuit shorted to VPWR.
  • Faulty MAF sensor or connector.
  • Faulty PCM.

  1. Check MAF Signal High Input To PCM

    Ensure freeze frame data is recorded. Ensure air induction system is okay. Repair if necessary. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. If DTC P0505 is present, see appropriate test and repair first. With scan tool connected, increase engine speed to 1500 RPM and return to idle. Access MAF PID. If PID reading is greater than 4.9 volts, go to next step. If PID reading is 4.9 volts or less, go to step Β 4.
  2. Check MAF SIG Circuit For Short To Power

    Turn ignition off. Disconnect MAF sensor. Start engine and allow to idle. Using scan tool, access MAF PID. If PID voltage reading does not drop to less than 1.0 volt, repair wiring and go to next step. If PID voltage reading does drop to less than 1.0 volt, replace MAF sensor and go to next step.
  3. Erase DTC

    Clear DTCs. Check for DTCs. If DTC P0103 returns, replace PCM and retest. If DTC P0103 does not return, go to next step.
  4. Erase DTC

    If any DTCs are present, go to appropriate test. If no DTCs are present, test is complete.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.