Beetle L4-1781cc 1.8L Turbo (APH) (1999)
A/C Signal: Testing and Inspection
Signal From/To Air Conditioning, Checking
Special tools, test equipment and auxiliary items
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Scan tool V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3B
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Test box V.A.G 1598/31
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Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
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Adapter set V.A.G 1594
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Wiring diagram
Test Conditions
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Fuses 5, 10 and 29 must be OK
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The battery voltage must be at least 11.5 V
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All electrical consumers, e.g. lights and rear window heating must be switched off
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No DTCs must be stored in DTC memory, checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With
Manufacturers Scan Tool/DTC Memory, Checking And Erasing", See: Testing and Inspection
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Air conditioner functioning OK
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Air conditioner must be switched off
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Vehicle at room temperature (warmer than +15°C)
Test sequence
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Connect scan tool V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine
must be running at idle speed. Connecting scan tool and selecting Engine Control Module (ECM). Refer to "Scan Tool Testing/Scan Tool
Connecting and Initial Checks/VAG 1551 Scan Tool", See: Testing and Inspection
Indicated on display
Rapid data transfer
HELP
Select function XX
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Press keys 0 and 8 for the function "Read measuring value block" and confirm entry with Q key.
Indicated on display
Read measuring value block
Input display group number XXX
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Press keys 0, 5 and 0 for "Display group number 50" and confirm entry with Q key.
Indicated on display (1-4 = Display zones)
Read measuring value block 50
->
1
2
3
4
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Check specifications for air conditioner (display zones 3 and 4)