Audi Workshop Service and Repair Manuals

Special tools, testers and auxiliary items

• ◆ Diode test lamp V.A.G 1527
• ◆ Fault reader V.A.G 1551 (or vehicle system tester V.A.G 1552) with cable V.A.G 1551/3
• ◆ Adapter set V.A.G 1594
• ◆ Test box V.A.G 1598/22

Testing operation

• ‒ Connect fault reader V.A.G 1551
  .
• ‒ Start the engine.
• ‒ Select "Read measured value block", Display Group 002, engine at idling speed.

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

• ◆ Specification: 3.0 ... 5.0 g/s

• ‒ If the values are not as specified or if the fault memory has recorded a fault relating to the air mass meter, test the power supply to the air mass meter.

Testing power supply to air mass meter

• ‒ Test fuse for air mass meter.

=> Current flow diagrams, Electrical fault-finding and Fitting locations

• ‒ → If the fuse is OK, connect diode test lamp V.A.G 1527 between engine earth and contact 3 on the plug connector.
• ‒ Switch on ignition. The diode test lamp should light up.
• ‒ → If the diode test lamp does not light up, test for open circuits or shorts to earth in wiring between fuse and contact 3 on plug connector. Rectify if necessary.

=> Current flow diagrams, Electrical fault-finding and Fitting locations

• ‒ If the power supply is OK, test the signal wiring
  => Page 24-53.

Testing signal wire for air mass meter

• ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit
  => Page 24-24.
• ‒ → Test wiring from plug connector on air mass meter...

• ‒ → ... to engine control unit for open circuit and short to positive or earth. Rectify if necessary.

• ‒ If the wiring is OK, fit a new air mass meter -G70.