Audi Workshop Service and Repair Manuals

Checking operation

• ‒ Select the function "Reading measured value block" (function 08) and Display Group 2
  .

Display zone 4 will show the intake air mass (grams per second).

• Specified value: 1.8...4.0 g/s

• ‒ If the specified values are not achieved or if there is a fault relating to the air mass meter in the fault memory, check the power supply to the air mass meter .

Checking the power supply to the air mass meter

• ‒ Check the fuse for the air mass meter.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations binder

• ‒ → If the fuse is OK, connect the V.A.G 1527 diode test lamp between contact 3 on the connector and the engine earth.
• ‒ Operate the starter briefly (the engine may start briefly).

The diode test lamp should light up.

• ‒ → If the diode test lamp does not light up, check the wiring from contact 3 on the connector via the fuse to the fuel pump relay for an open circuit or short to earth and rectify if necessary.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations binder

• ‒ If the fuse and the wiring are OK but the diode test lamp still does not light up, check the fuel pump relay => Page 24-26.
• ‒ If the power supply is OK, check the signal line => Page 24-33.

Checking signal line for the air mass meter

• ‒ Connect the V.A.G 1598/22 test box to the wiring harness for the engine control unit
  .
• ‒ → Check the wiring from the connector on the air mass meter...

• ‒ → to the engine control unit for an open circuit or short to positive or earth and rectify if necessary:

• ‒ If the power supply and the wiring are OK, replace the -G70 air mass meter.