Audi Cars 1999-05

Mass Air Flow (MAF) Sensor

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Removal & Installation



All Except Passat 2.0L
  1. Turn the ignition switch to the OFF position.
  2.  
  3. Disconnect the Intake Air Temperature sensor harness electrical connector.
  4.  
  5. Using a suitable tool, remove Intake Air Temperature sensor.
  6.  
  7. Installation is in reverse order of removal.
  8.  

Testing




NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  


NOTE
Use only gold-plated terminals when servicing the terminals in the harness connector of the Mass Air Flow (MAF) Sensor.

  1. Connect the vehicle to the diagnosis and service system.
  2.  
  3. Start the engine and let it run at idle.
  4.  
  5. Under address word "33 - On Board Diagnostic (OBD)", select "Diagnostic mode 1: Check measured values" .
  6.  
  7. Select measuring value "PID 16: Air flow quantity at Mass Air Flow (MAF) sensor" .
  8.  
  9. Check the specified value of the air flow quantity at the Mass Air Flow (MAF) Sensor at idle.
  10.  
  11. End the diagnosis and switch the ignition off.
  12.  
  13. If the specified value is obtained but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor, check the voltage supply of the Mass Air Flow (MAF) Sensor.
  14.  
  15. If the specified value is not obtained, check the wires of the Mass Air Flow (MAF) Sensor.

    Click image to see an enlarged view

    Fig. Disconnect the 5-pin harness connector (1) at Mass Air Flow (MAF) Sensor

  16.  
  17. Disconnect the 5-pin harness connector at the Mass Air Flow (MAF) Sensor.
  18.  
  19. Start the engine and let it run at idle.
  20.  
  21. Measure the voltage between terminal 3 of connector and the engine ground (GND) using a multimeter and the adapter cables from the connector test kit.
  22.  
  23. Specified value: approx. battery voltage
  24.  
  25. Switch the ignition off.
  26.  
  27. If the voltage is not okay, check the wire between the 5-pin connector terminal 3 and the Engine Component Power Supply Relay for an open circuit.
  28.  
  29. Wire resistance: max. 1.5 ohms
  30.  
  31. If the voltage supply is okay, checking the wiring.
  32.  
  33. Connect the test box to the wiring harness of the Motronic Engine Control Module (ECM).

    Click image to see an enlarged view

    Fig. Check wires between test box and 5-pin connector for open circuit.

  34.  
  35. Check the wires between the test box and the 5-pin connector for an open circuit.

    Terminal 1 and socket 22
     
    Terminal 2 and socket 1
     
    Terminal 2 and socket 2
     
    Terminal 2 and socket 4
     

  36.  
  37. Wire resistance: max. 1.5 ohms
  38.  
  39. Check the wires for short circuit to each other, to Battery (+) and Ground (GND).
  40.  
  41. Specified value: infinite ohms
  42.  
  43. If the wires are okay, replace Mass Air Flow (MAF) Sensor.
  44.  

1.8L, 2.7L, 2.8L

NOTE
For this check, all electrical accessories should be switched off (coolant fan must not run during test). Ensure the fuse for the MAF sensor is OK.

  1. Connect a VAG 1551 or VAG 1552 scan tool and press buttons '0' and '1' to insert 'Engine Electronics' address word 01 (with engine running at idle).
  2.  
  3. Press buttons '0' and '8' to select 'Read Measuring Value Block' function 08 , and press 'Q' button to confirm input.
  4.  
  5. Press buttons '0', '0' and '2' to input display group number 2 , and press the 'Q' button to confirm input.
  6.  
  7. Compare the display with the specified values for engine load.
  8.  



Click image to see an enlarged view

Fig. Showing the MAF sensor connector

  1. Disconnect the 3-pin harness connector from the MAF sensor.
  2.  
  3. Connect a DMM between harness connector terminal 3 and engine ground, using adapter cables from VW1594 connector test kit.
  4.  
  5. Switch the ignition to 'ON' and measure the voltage. It should be 11.5 volts.
  6.  
  7. Switch ignition to 'OFF'.
  8.  

If the voltage specification is not attained, check the wiring from terminal 3 to fuse panel, using an applicable wiring diagram.

  1. Connect a VAG1598/22 test box to the ECM harness connector.
  2.  
  3. Check wiring for open circuits between the ECM/test box and the 3-pin MAF sensor harness connector. Check at the following points:
  4.  


    Connector terminal 1 to ECM test box socket 13
     
    Connector terminal 2 to ECM test box socket 12
     


The value should be a maximum resistance of 1.5 ohms at each test point.

  1. If not, check the wiring for short circuits between terminals of 3-pin connector. The DMM should show infinite ohms.
  2.  
  3. If the voltage supply and wiring are OK, replace the Mass Airflow (MAF) sensor-G70.
  4.  

 
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