100 Quattro Sedan L5-2309cc 2.3L SOHC (NF) (1989)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
CIS-E III Control Unit Harness Connectors (Pin # Locations)
CIRCUIT TEST
1.
Disconnect harness connector from fuel control unit.
2.
Using DVM set to appropriate K ohms scale, test resistance between harness connector terminal #3 and ground.
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Resistance should be in the range shown in diagram for a given temperature.
Coolant Temperature Sensor Resistance vs. Temperature
If resistance is higher than specified (or infinite), check for:
a. Poor connections or corroded connector terminals at sensor.
b. Open circuit between fuel control unit terminal #3 and sensor connector terminal #2.
c. Faulty sensor.
If resistance is lower than specified (or zero), check for:
a. Grounded circuit between fuel control unit terminal #3 and sensor.
b. Faulty sensor.
3.
Disconnect harness connector from ignition control unit.
4.
Using DVM set to appropriate K ohms scale, test resistance between harness connector terminal #25 and ground.
-
Resistance should be in the range shown in diagram for a given temperature.