Audi A3 Workshop Service and Auto Repair Manuals

Testing operation

Test conditions

• ● Vehicle stationary, engine idling.

• ‒ Select Read measured value block (function 08) and Display Group 02 ).

Display zone 2 shows the intake air mass (milligrams per stroke).

Specification: 76...164 mg/stroke

• ‒ 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, unplug the connector from -G70 and connect diode test lamp V.A.G 1527 between engine earth and contact 3 on the connector.
• ‒ Operate the starter briefly (the engine can be allowed to start briefly). 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 from contact 3 on plug connector to fuse - if necessary repair the wiring.

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

• ‒ If the fuse and the wiring are OK but the diode test lamp still does not light up, test the fuel pump relay => Page 24-30.
• ‒ If the power supply is OK, test the signal wire => Page 24-37.

Testing signal wiring for air mass meter

• ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit
  .
• ‒ → 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).