Jetta Wagon L4-1.9L DSL Turbo (ALH) (2003)
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A/C Signal: Testing and Inspection
With Manufacturer's Scan Tool
A/C System Signals, Checking
Special tools and equipment
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Scan Tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3
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Test box VAG 1598/31
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Hand multimeter VAG 1526 or multimeter VAG 1715
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Adapter set VAG 1594
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Wiring diagram
Test conditions
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The battery voltage must be at least 11.5 V.
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A/C functioning OK.
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No malfunctions must be stored in DTC memory, interrogating fault memory.
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Vehicle at room temperature (warmer than + 15 degree C).
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All electrical accessories, e.g. lights and rear window heating must be switched off
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A/C switched on.
Compressor shut-off, checking
The A/C control head signals the Diesel Direct Fuel Injection Engine Control Module -J248- that the A/C compressor will be switch on, via the A/C
compressor signal.
Through another wiring connection, the engine control has the possibility of switching off the air conditioner compressor for various operating
conditions:
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Hard acceleration from low speed
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Emergency program (emergency running operation)
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Coolant temperatures above + 120 C (248 F)
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After every engine start for approx. 6 seconds.
Test sequence
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Connect Scan Tool VAG 1551 ((VAG 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine
must be running at idling speed. (Connecting Scan Tool and selecting engine electronics control unit.)
Rapid data transfer
HELP
Select function XX
Indicated on display:
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Press buttons -0- and -3- for the function "Output Diagnostic Test Mode".
Rapid data transfer
Q
03 Final control diagnosis
Indicated on display:
-
Confirm input with -Q- button.
Final control diagnosis
->
Commencement of injection valve -N108
Indicated on display:
-
Press the -> button.
Final control diagnosis
->
Exhaust gas recirculation valve -N18
Indicated on display:
-
Press the -> button.
Final control diagnosis
->