Volkswagen Workshop Service and Repair Manuals

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 (address word 01); carry out selection at idling.
  => Page 01-4

• ‒ Input 08 for "Read measured value block" function and confirm with Q.

• ‒ Input 05 for display group 05 and confirm with Q.

• ‒ Observe display zone 4 -5 digit number block-:

• 1st + 2nd position from left must display zero
       Display 0000

• ‒ Switch on air conditioner (lowest temperature and highest blower speed).

• 1st + 2nd position from left must now display 1
       Display 1100

If the display does not indicate as described:

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wiring between test box sockets 37 and 39 and air conditioner for open circuit according to current flow diagram
       Wire resistance: Max. 1.5 ω