Eurovan V6-2792cc 2.8L (AES) (1998)
A/C Signal: Testing and Inspection
A/C Compressor (On/Off Signal), Checking
A/C compressor ON signal
Voltage is supplied to the engine control module shortly before switching on the air conditioner compressor. The signal ensures that the control module
keeps the idling speed constant for the differing power requirements of the air conditioning system.
A/C compressor OFF signal
The air conditioner compressor is switched off for approx. 12 seconds by the engine control module when accelerating from a standstill and from low
speeds to ensure that the full engine power is available. If the accelerator is released earlier the time is shortened to a minimum of 3 seconds. At wide
open throttle the air conditioner is switched off by the transmission control module (kick down switch).
Special tools and equipment
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VAG 1551/1552 Scan Tool using VAG. 1551/3 adapter cable
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VAG 1598/18 Test Box
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Fluke 83 multimeter (or equivalent)
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VW 1594 Adapter kit
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Wiring diagram
Test conditions
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A/C functions OK
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A/C switched off
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Vehicle interior temperature: 15 °C (59 °F) minimum
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No malfunctions (DTC's) stored in DTC memory.
Test sequence
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Connect VAG 1551 (VAG 1552) Scan Tool. Refer to Scan Tool Testing/VAG 1551 Scan Tool. See: Testing and Inspection
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With engine idling, press buttons -0- and -1- to select "Engine Electronics" address word 01.
Display will appear as shown
Rapid data transfer
HELP
Select function XX
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Press buttons -0- and -8- to select "Read measuring value block".
-
Press -Q- button to enter selection.
Display will appear as shown
Read measuring value block
HELP
Input display group number XXX
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Press buttons -0-, -0- and -8- to select "Display group number 8".
-
Press -Q- button to enter selection.
Display will appear as shown (1 to 4 = Display fields)
Read measuring value block 8
->
1
2
3
4
-
Check A/C specifications (Display fields 3 and 4).