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 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 01-6 .)

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

• ‒ Press keys 0, 0 and 8 for "Display group number 8" and confirm entry with Q key.

• ‒ Switch on air conditioner (lowest temperature and highest blower speed).
• ‒ Check specifications for air conditioner (display zones 3 and 4)

Note:

The air conditioner compressor will be switched off (Compr. OFF) when the engine control unit recognises full load and the air conditioning is switched on (A/C-HIGH).

Continuation

If the display does not indicate as described:

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

If the specification is not obtained:

• ‒ Check wiring according to current flow diagram.