Beetle L4-1781cc 1.8L Turbo (APH) (1999)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
With Manufacturer's Scan Tool
Engine Coolant Temperature (ECT) Sensor, Checking
NOTE: The Engine Control Module (ECM) will use a replacement temperature value for an engine start as soon as there is a DTC stored in the DTC
memory which affects the Engine Coolant Temperature (ECT) sensor -G62-. The temperature then rises according to a model stored in the ECM. When
the engine has reached normal working temperature a fixed replacement value will be displayed after a certain period. This fixed value is also dependent
on intake air temperature.
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 VAG 1715
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Adapter set V.A.G 1594
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Wiring diagram
Test conditions
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Engine must be cold
Test sequence
NOTE: Only gold-plated contacts must be used to repair the contacts 1 and 3 in the connector for the Engine Coolant Temperature (ECT) sensor.
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Connect the scan tool V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control module with the "Address word" 01.
Connecting scan tool and selecting Engine Control Module (ECM). See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool Connecting/With Manufacturer's Scan Tool/Connecting VAG 1551 Scan
Tool
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, 0 and 4 for "Display group number 4" and confirm entry with Q key.
Indicated on display (1-4 = Display zones)
Read measuring value block 4
->
1
2
3
4
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Read off coolant temperature value in display zone 3.