Home ReviewsRefund
Home/Subaru/Impreza/Subaru Impreza GC/GF (1992-2000)/Repair manual/Testing & Diagnostics/DTC P0100 (QA) - MASS AIR FLOW (MAF) SENSOR CIRCUIT MALFUNC…
Contents Wiring diagrams Section: Testing & Diagnostics All sections

DTC P0100 (QA) - MASS AIR FLOW (MAF) SENSOR CIRCUIT MALFUNCTION Subaru Impreza GC/GF

Testing & Diagnostics ~391 words

Note. Refer to illustration for connector and terminal identification. (Схема №11)- (Схема №29).

  1. Turn ignition to OFF. After Connecting SSM or OBD-II scan tool, turn ignition to ON. Turn SSM or OBD-II scan tool to ON. Start Engine. Set function mode on SSM to F08 to read voltage output from MAF sensor or F47 to read mass air flow in g/sec. If sensor output voltage is 0.3-5.0 volts and/or mass air flow is 1.3-250 g/sec, check for a poor connection, short or open in sensor circuit or ground wires and repair as necessary. If value reading is less than 0.3 volt (1.3 g/sec), go to step 2). If wiring is good and reading is more than 0.3 volt (1.3 g/sec), go to step 5).
  2. Measure voltage between ECM connector E29, terminal No. 26 and ground. If voltage is 0.3 volt or less, go to next step. If voltage is more than 0.3 volt while shaking harness and connector, repair contact in ECM connector. If voltage remains below 0.3 volt, replace ECM.
  3. Turn ignition to OFF. Disconnect connector from MAF. Turn ignition to ON. Measure voltage between MAF connector E25, terminal No. 1 and ground. If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open circuit in harness between main relay connector and MAF connector.
  4. Turn ignition to OFF. Disconnect ECM connector. Measure resistance of harness between ECM connector E29, terminal No. 26 and MAF connector E25, terminal No. 4, between ECM connector E29, terminal 46 and MAF connector E25, terminal No. 3, and between ECM connector E29, terminal No. 25 and MAF connector E25, terminal No. 2. If resistance is one ohm or less in each or any instance, replace MAF sensor. If resistance is more than one ohm, repair poor contact or open circuit in harness between ECM and MAF sensor connector.
  5. Turn ignition to OFF. Disconnect MAF sensor connector. With SSM connected, turn ignition to ON. Turn SSM ON and select function mode F08. If voltage reads more than 5 volts, repair short in harness between ECM and MAF. If voltage is less than 5 volts, check for poor contact in MAF sensor connector. If contact is bad, repair as necessary. If contact is okay, replace MAF sensor.

More articles — Engine Controls - Tests W/codes