Jetta GL L4-1.9L DSL Turbo (ALH) (2001)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
With Manufacturer's Scan Tool
Engine Coolant Temperature (ECT) Sensor, Checking
NOTE: Only gold-plated contacts must be used to repair terminals 1 and 3 in the connector for the ECT sensor.
Special tools and equipment
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V.A.G 1551/1552 Scan tool with adapter cable V.A.G 1551/3
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Test box VAG 1598/22 (through my 1999)
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Test box VAG 1598/31 (from my 2000)
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Digital multimeter US1119 (Fluke 83 or equivalent)
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Adapter set VAG 1594
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Wiring diagram
Test conditions
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Engine must be cold.
Test sequence
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Connect V.A.G 1551/1552 (Connecting scan tool and selecting engine electronics control module.) See: Powertrain Management/Computers and
Control Systems/Testing and Inspection
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Run engine at idle speed and press buttons -0- and -1- to select "Engine electronics" address word 01.
Indicated on display
Rapid data transfer
HELP
Select function XX
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Press buttons -0- and -8- to select "Read measured value block" function 08 and confirm entry with -Q- button.
Indicated on display
Read measured value block
HELP
Input display group number XXX
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Press buttons -0-, -0- and -7- to select "Display group number 7" and confirm entry with -Q- button.
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Indicated on display
Read measured value block 7
->
15.4 °C
15.9 °C
16.7 °C
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Observe coolant temperature figure in display field 4.
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The temperature figure must increase uniformly and without interruption.
In the case of a malfunction the fuel temperature is displayed as a substitute.
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Press the -> button.
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Press buttons -0- and -6- to select "End output" function 06 and confirm entry with -Q- button.
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Switch ignition off.
If the display in field 4 appears unrealistic or the fuel temperature is displayed as a substitute, check the ECT sensor and wiring connections to the sensor
as follows: