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

Fitting location => Fitting locations 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 and select vehicle system "01 -Engine electronics" in the selection. For this purpose, the engine must be running at idling speed.

→ Display on VAS 5051:

• ‒ Under -1- select the diagnostic function "04 - Basic setting".

→ Display on VAS 5051:

•     1 -    Enter display group
  max. input value = 255

• ‒ Enter "002" for "display group number 002" in zone -2- and confirm the entry by pressing the Q key.

→ Display on VAS 5051:

• ‒ Check specifications for load recognition in display zones -3- and -4-.

If specified value is attained:

• ‒ Exit the function "04 - Basic setting" by pressing the ◂ key.

Evaluation of display group 002

Checking voltage supply to air mass meter

Test requirements:

• ● Fuse for air mass meter OK.

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

• ● Fuel pump relay OK; checking .

Note:

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

• ‒ Detach connector from 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 binder

• ‒ Rectify any open/short circuit as necessary.

• ‒ → Connect hand-held multimeter to contacts 2 and 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 contacts 3 and 4 of the connector to measure voltage.
• ‒ Specified value: approx. 5 V

If specified value is not attained:

• ‒ Check the wiring connections
  .

Checking wiring to air mass meter.

Note:

The signal wire is also checked during the wiring check.

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit; do not connect the engine control unit => 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).