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Home >> Mazda >> 1998 >> B3000 SX, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Testing >> Diagnostic Trouble Codes >> DTC P0103: Mass Airflow (MAF) Sensor >> Condition

DTC P0103: Mass Airflow (MAF) Sensor: Condition

DTC indicates MAF signal was more than 3.9 volts sometime during normal engine operation. Possible causes for this fault are:

  1. Check MAF Signal High Input To PCM

    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. With scan tool connected, increase engine speed to 1500 RPM and return to idle. Access MAF PID. PID reading should be more than 3.90 volts. Turn ignition off. Disconnect MAF sensor. Start engine and allow to idle. Access MAF PID. If PID voltage reading does not drop to less than 0.39 volt, go to next step. If PID voltage reading does drop to less than 0.39 volt, replace MAF sensor.
  2. Check MAF SIG Circuit For Short To Power

    Leave ignition off and MAF sensor disconnected. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 88 (MAF SIG) and test pins No. 24 and 103 at breakout box. If voltage is less than 10.5 volts, go to next step. If voltage is 10.5 volts or more, repair MAF SIG circuit short to power.
  3. Check MAF SIG Circuit For Short To Power In PCM

    Leave ignition off and MAF sensor disconnected. Disconnect scan tool from DLC (if applicable). Measure resistance between test pins No. 88 (MAF SIG) and No. 90 at breakout box. If resistance is more than 10 k/ohms, replace PCM and repeat QUICK TEST. If resistance is 10 k/ohms or less, repair short between MAF SIG and VREF circuit. Repeat quick test. See QUICK TEST in TESTS W/CODES - INTRODUCTION article.