Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31
• ◆ VAS 5051 with VAS 5051/1

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Fitting location => Fitting location overview Page 24-5

Test requirements:

• ● Coolant temperature at least 80 °C.
• ● Electrical consumers switched off (radiator fan must not run during the test)
• ● Air conditioning switched off.

checking function

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "Address word" 01
  For this purpose, the engine must be running at idle speed

• ‒ Enter "04" to select "Start basic setting" and confirm with Q key.

• ‒ Enter "002" for "display group number 002" and confirm entry with Q key.

• ‒ Check specified results for recorded load.

If specified value is attained:

• ‒ Press the ⇒key.

Interpreting display group 002

Testing voltage supply to air mass meter

Test requirements:

• ● Fuse for air mass meter OK.

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

• ● Fuel pump relay OK; checking .

Note:

Voltage supply to air mass meter is from fuel pump relay.

• ‒ Disconnect connector from intake air mass meter.

• ‒ → Connect multimeter as follows to measure voltage.

• ‒ Operate the starter briefly (the engine may start).
• ‒ Specified value: approx. battery voltage

If specified value is not attained:

• ‒ Check the wiring from contact 2 on the connector via the fuse to the fuel pump relay for open circuit or short to earth:

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

• ‒ Rectify any open/short circuit as necessary.

• ‒ → Connect hand-held multimeter to contact 2 and contact 3 of the connector to measure voltage.
• ‒ Operate the starter briefly (the engine may start).
• ‒ Specified value: approx. battery voltage

Note:

Engine control unit earth is present at contact 3 of the connector.

If specified value is not attained:

• ‒ Check the wiring connections
  .

• ‒ → Connect hand-held multimeter to contact 3 and contact 4 of the connector to measure voltage.
• ‒ Specified value: approx. 5 V

If specified value is not attained:

• ‒ Check the wiring connections
  .

Check wiring to air mass meter

Note:

The signal wire is also checked during the wiring check.

• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit should not be connected => Page 24-19.

• ‒ → Check for open circuit and short to positive or earth in the following wiring connections:

• ‒ Rectify any open/short circuit as necessary.
• ‒ Additionally check all wires for short to one another.

If the wiring is OK:

• ‒ Renew air mass meter -G70.