With VAG
CHECKING ENGINE COOLANT TEMPERATURE SENSORREQUIREMENTS
^ Test using VAG 1551 Scan Tool (ST) with engine idling.
^ Engine cold.
^ VAG 1551 Scan Tool connected with "Read Measuring Value Block" function selected (display group number 1).
PROCEDURE
^ Indicated on display (1 - 4 = display fields)
Read measuring value block 1 -->
1 2 3 4
- Read coolant temperature value in display field 2.
- Temperature value must increase uniformly without interruption.
NOTE:
- If the temperature display increases in jumps of 2 to 5°C, this is caused by the Motronic Engine Control Module (ECM) and not by a malfunctioning Engine Coolant Temperature (ECT) Sensor.
- 77°C will be displayed if this temperature is reached, or if there is an interruption (open circuit).
- If malfunctions and irregular engine running occur in certain temperature ranges, and the temperature value does not increase without interruption, then the temperature signal has been temporarily interrupted and the sensor must be replaced.
- Press --> button.
- Press buttons -0- and -6- to select the "End Output" function.
- Press -Q- to confirm input.
- If temperature value does not change:
- Perform electrical testing. Refer to Diagnostic Charts / VAG 1598 Pin Out Box / Electrical Checks / Test Step 17. Testing and Inspection
- If necessary replace Engine Coolant Temperature Sensor (G62).
CAUTION: Reduce pressure in the cooling system before replacing ECT Sensor.