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Home >> Volvo >> 1995 >> 850 Base, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - Non-Turbo >> Engine Sensors & Switches >> Mass Airflow Meter/Sensor

Mass Airflow Meter/Sensor

  1. Connect Breakout Box (981-3190 ) and Adapter (981-3195 ) to fuel injection ECU. See Figure . DO NOT measure resistance and voltage at ECU connector. Before disconnecting/connecting control unit connector, disconnect negative battery cable.
  2. Remove ECU cover located in right front engine compartment. Remove both fuel injection and distributor ignition ECUs located in right front of engine compartment. Press adapter into ECU base. Position adapter lead at rear of ECUs and thread through slot next to distributor ignition module.
  3. Press distributor ignition ECU into position first to avoid damage to adapter lead. Press fuel injection control unit, with adapter connected, into connector in bottom of ECU box. Connect breakout box to adapter 60-pin connector.
  4. Turn ignition on. Connect voltmeter between breakout box terminals No. 13 and 20. About 2.7 volts should be present. Start engine. About 3.5 volts should be present at idle with engine hot. Turn engine off. If voltages are okay, go to step 6) and check MAF ground circuit. If voltages are not okay, go to next step.
  5. Turn ignition on. Connect voltmeter between MAF connector terminal No. 4 (White wire) and ground. Voltage should be about 2.7 volts. Start engine. Voltage should be about 3.5 volts during idle with engine hot. If voltages are correct, check voltage supply for an open or short circuit. If voltages are incorrect, go to next step and check MAF ground circuit.
  6. Turn ignition off. Connect ohmmeter between MAF connector terminal No. 2 (Green/Red wire) and ground, then between connector terminal No. 1 (Brown/White wire) and ground. Ohmmeter should indicate about zero ohms in both instances. If readings are okay, go to step 8). If readings are incorrect, go to next step.
  7. Ensure ignition is off. Connect ohmmeter between breakout box terminals No. 20 and 8, then between terminals No. 20 and 12. Ohmmeter should indicate about zero ohms in both instances. If readings are incorrect, repeat test using new fuel injection ECU. If readings are correct, go to next step and check MAF voltage supply.
  8. Turn ignition on. Connect voltmeter between ground and MAF connector terminal No. 3 (Green wire). Voltmeter should indicate battery voltage. If voltage is not present, check for an open or short circuit in voltage supply. If voltage is present, repeat test using new MAF sensor.
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