A6 Quattro Sedan V6-3.2L (BKH) (2005)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Engine Coolant Temperature Sensor, Checking
CAUTION!
‹› Cooling system is under pressure.
‹› Danger of scalding when opening!
‹› Use only gold-plated terminals when servicing terminals in the electrical harness connector of Engine Coolant Temperature (ECT) Sensor (G62).
Special tools, testers and auxiliary items required
‹› Multimeter.
‹› Wiring diagram.
Test requirements
‹› The Engine Control Module (ECM) (J623) fuses OK.
‹› Battery voltage at least 12.5 V.
‹› All electrical consumers such as, lights and rear window defroster, switched off.
‹› Vehicles with automatic transmission, shift selector lever into position " P" or "N".
‹› A/C switched off.
‹› Ground (GND) connections between engine/transmission/chassis OK.
‹› Ignition switched off.
‹› Engine cold.
Test procedure
-
Perform a preliminary check to verify the customer's complaint. Refer to => [ Preliminary Check ] See: Powertrain Management/Computers and
Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/Preliminary Check.
-
Connect the scan tool.
-
Switch the ignition on.
-
Using the scan tool, check the coolant temperature:
‹› If a temperature is indicated which differs greatly from the ambient temperature of the sensor, check the sensor and wiring for contact resistances
and open circuits.
If the specified value is obtained:
-
Start the engine and let it run at idle.
The temperature value must increase uniformly in increments of 10 °C.
‹› If the engine shows problems in certain temperature ranges and if the temperature does not climb uniformly, the temperature signal is intermittent
and the sensor should be replaced.
-
Replace the the Engine Coolant Temperature (ECT) Sensor (G62) => Fuel Injection and Ignition 19 Removal and Installation.
-
End diagnosis and switch the ignition off.