SEAT Workshop Service and Repair Manuals > Leon Mk1 > Power unit | 4LV Injection and Ignition System | Mixture preparation system, electronic inj.,Gas | Additional signals checking | Signals from/to air conditioning system: checking

Signals from/to air conditioning system: checking

Special tools and workshop equipment required

t	Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3B-

t	Test box -V.A.G 1598/31-

t	Hand multimeter -V.A.G 1526 A- or multimeter -V.A.G 1715-

t	Adapter set -V.A.G 1594 C-

t	Current flow diagram

Check conditions

l	Air conditioner functioning OK

l	Air conditioner must be switched off

l	Vehicle at room temperature (warmer than + 15 °C).

l	No faults must be stored in fault memory → Chapter, Fault memory: consulting.

Test sequence

–	Connect fault reader -V.A.G 1551/V.A.G 1552-. Start engine and select “Address code” 01 of engine control unit. (Fault reader: Connecting and selecting the engine control unit → Chapter).

Indicated on display:

–	Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q -key.

Rapid data transfer            HELP

Select function XX

Indicated on display:

–	Press keys 0, 5 and 0 for “Display group number 50” and confirm entry with Q -key.

Read measured value block    HELP

Input display group number XXX

Indicated on display: (1...4 = Display fields)

Check reading in display field 4. It should read

Compr NO

–	Switch on air conditioning system.

–	Select lowest temperature and highest blower speed.

The display in display field 4 must change to

Compr YES:

–	Press → -key.

–	Press keys 0 and 6 for the “End output” function and confirm input with the Q -key.

–	Switch off ignition.

If the display does not change:

Read measured value block 50          ->

       1         2         3         4

–	Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.

–	Check wiring between test box sockets 40+41 and air conditioner for open circuit using current flow diagram.

Resistance: max. 1.5 Ω

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