Volkswagen Workshop Service and Repair Manuals

Only engine codes AGG and AFT.

On vehicles with engine code ADY the wiring can only be checked with test box V.A.G 1598/18.

Special tools, testers and auxiliary items

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● Function of air conditioner OK.
• ● Air conditioner switched off
• ● Interior of vehicle has room temperature (above 15 ° C)
• ● No faults stored in fault memory
  , interrogating fault memory

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine electronics control unit => Page 01-3 .)

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

• ‒ Observe 8 digit number block in display zone 4. 3rd position from left must display 0.
       Display: 00000000
• ‒ Switch on air conditioner. Adjust lowest temperature and highest blower stage.

• 3rd position from left must now display 1
       Display: 00100000

If the display does not change:

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wiring between test box sockets 13 and 39 and the air conditioner for open circuit according to current flow diagram.
       Wire resistance: Max. 1.5 ω