Passat L4-1984cc 2.0L DOHC (1991)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Coolant Temperature Sensor, Checking
The following procedure applies to vehicles built after 10-90 starting with control units:
49 states: 8A0 907 404
California: 893 901 404
For vehicles built before 9-90 check the speedometer signal by performing electrical test steps 8 and 23 in Repair Group D2.
Requirements
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engine cold
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connect VAG 1551 Diagnostic Tester using VAG 1551/1 adaptor wire as follows:
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first connect black connector from VAG 1551/1 to black diagnostic connector 1
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after "VAG SELF-DIAGNOSIS" display appears, connect white connector from VAG 1551/1 to brown and/or white diagnostic connector 2
If display does not appear; do not connect white connector
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check voltage supply to VAG 1551 using wiring diagram
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start engine and let idle
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press 1 button to enter "rapid data transfer"
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press 0 and 1 for address word "engine electronics"
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press Q button to enter input
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press -> button
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press 0 and 8 buttons to obtain "Read measurement block" function
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press Q button to enter input
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display will appear as shown
Read measurement block
HELP
Input display group number XX
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press 0 button twice to select display group 00
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display will appear as shown
Read measurement block
Q
Input display group number 00
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press Q to enter input
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display shows channels 1 through 10
Read measurement block
-->
1
2
3
4
5
6
7
8
9
10
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observe value in channel 1