Audi Workshop Service and Repair Manuals

Special tools, testers 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

Test requirements:

• ● Coolant temperature at least 80 oC.
• ● Electrical consumers switched off (radiator fan must not run during the test)
• ● Air conditioning switched off.
• ● Fuse for airflow meter OK.

=> "Current Flow Diagrams, Electrical Fault Finding and Installation locations" binder

Check function

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

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

Note:

During basic setting, the solenoid valve for the active carbon canister (valve -N80) is closed and the air conditioning compressor is switched off.

• ‒ Enter "002" to select "Display Group 002" and confirm entry with the Q key.

• ‒ Check specified results for recorded load.

If the specified value is attained:

• ‒ Press the ⇒key.

Interpreting display group 002

Interpreting display group 002

Testing voltage supply to air mass meter

• ‒ Disconnect connector from intake air temperature sensor.

• ‒ → Connect up multimeter as follows to measure voltage.

• ‒ Operate starter briefly.
• ‒ Specified value: approx. battery voltage

Note:

Voltage supply to airflow meter is from fuel pump relay.

If the specified value is not attained:

• ‒ → Test wiring from contact 3 on connector via fuse S234 (in fuse box, position 34) to fuel pump relay for open circuit or short to earth.

=> "Current Flow Diagrams, Electrical Fault Finding and Installation locations" binder

• ‒ Rectify any open/short as necessary.

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

Note:

Engine control unit earth is present at contact 2 of the connector.

If the specified value is not attained:

• ‒ Check the wiring
  => Page 24-63.

• ‒ → Connect hand-held multimeter (voltage test range) to contact 1 and contact 2 of the connector.
• ‒ Switch on the ignition.
• ‒ Specified value: approx. 5 V.

If the specified value is not attained:

• ‒ Check the wiring
  => Page 24-63.

Check wiring to airflow 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 24-20.

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

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

If the wiring is OK:

• ‒ Replace airmass meter -G70.