Passat Wagon V6-2792cc 2.8L DOHC (1994)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Coolant Temperature Sensor, Checking
Testing without VAG 1551
Fig. 3 Temperature sensors I & II operating specifications
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Check temperature and resistance of Engine Coolant Temperature (ECT) sensor.
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If resistance is not within specifications on graph replace ECT sensor.
Testing with VAG 1551
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Engine must be cold to observe sensor through out range
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Connect and start operation of VAG 1551 Refer to Connecting and Operating VAG 1551 Scan Tool
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Start engine and let idle
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select function 08 "Read test value block" Refer to VAG w/ VAG 1551- Test Value Block, Reading
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Select display group 01, display will appear as shown:
Read test value block 1
1 2 3 4
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Observe display value in field 2
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Engine temperature must be uniform and increase without interruption
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Select function O6 "Ending output"
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If displayed value does not increase
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Perform electrical checks, Refer to VAG 1598 Pin Out Box/ Electrical Checks,Test step 18
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If necessary, replace sensor
Note:If engine malfunctions occur during certain temperature ranges and the display value does not increase without interruption. Temperature
signal has been interrupted and the ECT sensor must be replaced.