Jetta GL L4-1.9L DSL Turbo (ALH) (2001)
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 (ST) VAG 1551/1552 with cable VAG 1551/3
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VAG 1598/22 test box
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Digital multimeter US 1119 (Fluke 83 or equivalent)
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VAG 1594 adapter kit
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Wiring diagram
Test conditions
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A/C function OK.
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No DTCs stored in DTC memory.
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All electrical consumers, e.g. lights and rear window heating switched off.
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Battery 11.5 volts minimum.
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Vehicle at room temperature.
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A/C switched on.
Compressor shut-off, checking
The A/C control head signals the Engine Control Module (ECM) -J248- that the A/C compressor will be switch on, via the A/C compressor signal.
Using the same wiring, the A/C compressor is switched off by the ECM under the following circumstances:
NOTE:
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Hard acceleration from low speed
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In emergency program (limp mode)
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Engine Coolant Temperatures exceeds + 120 °C (248 °F)
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After every engine start for approx. 6 seconds.
Checking
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Connect VAG 1551/1552 Scan Tool.
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Start engine and let idle.
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Press -0- and -1- buttons to select address word 01: Engine electronics".
Indicated on display:
Rapid data transfer
HELP
Select function XX
-
Press buttons -0- and -3- for "Output Diagnostic Test Mode" and confirm with -Q- button.
Indicated on display:
Rapid data transfer
Q
03 Output Diagnostic Test Mode
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Confirm input with -Q- button.
Indicated on display:
Output Diagnostic Test Mode
->
Commencement of injection valve -N108
-
Press -> button.
Indicated on display:
Output Diagnostic Test Mode
->
Exhaust gas recirculation valve -N18
-
Press -> button.
Indicated on display: