A6 Quattro Wagon V6-2.8L (AFC) (1995)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
NOTE:
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For functional testing of the Engine Coolant Temperature (ECT) sensor, Also Refer to On Board Diagnostic, "Read Measuring Value Block"
function 08, display group 001, display field 1.
PROCEDURE
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Disconnect ECT sensor harness connector.
Engine Coolant Temperature Sensor
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Check resistance between terminals 1 and 2 of sensor. Specified values:
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At approx. 20°C (68°F) coolant temperature, approx. 2.5K ohms
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At approx. 80°C (176°F) coolant temperature, approx. 330 ohms
If specified values are not obtained:
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Replace ECT sensor.
If specified value is obtained, check wiring from sensor to ECM as follows:
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Connect VAG 1598 test box with VAG 1598/11 adapter harness to ECM wiring harness. See: Testing and Inspection/Scan Tool Testing and
Procedures/Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting and Testing VAG 1598 Pin Out Box
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Adapter harness is not connected to ECM.
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Check Ground (GND) wire for continuity between ECT sensor connector terminal 2 and GND.
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Specified value: maximum 1.0 ohm
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Check signal wire for continuity between ECT sensor connector terminal 1 and test box socket 15.
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Specified value: maximum 1.0 ohm
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Check both wires for short to each other.
If specified values are not obtained:
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Repair short and/or break in wiring between ECT sensor and ECM connector -C- and/or GND.
ECT sensor
ECM connector C
connector terminal
terminal
1
15
2
Ground(GND)
If there is no short or break in wiring, and ECT sensor is OK:
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Replace ECM.