Coolant Light Flashing: Skoda Octavia AGR Fix

Hello everyone,

My vehicle: Skoda Octavia, 1.9 liter engine, 90 horsepower, engine code AGR, 120,000 km mileage, manufactured in 1998.

The problem: The coolant temperature warning light beeps three times after starting the engine and then flashes. After about 2 minutes of driving, the light goes off. When the engine is just turned on (without starting), the light stays on constantly. This problem only started when the outside temperatures became colder.

The manual states that this blinking light is caused by either an excessively high coolant temperature or insufficient coolant levels.
The 'search function' indicates that the coolant level sensor may be clogged or defective, and the temperature sensor G62/G2 is also prone to failure.

Vagcom reports no errors in the instrument cluster (KI) or the modular solid-state gateway (MSG).
'Measurements taken with VAGcom while the engine was running showed: The fuel, intake air, and coolant temperatures differ by approximately 3 degrees Celsius in the MSG. Is this still acceptable?'

'However, the instrument cluster control unit displays a coolant temperature of 30 degrees, which cannot be correct. I then connected a 10k potentiometer to the sensor connector. However, I was unable to set any temperature values below 30 degrees using the potentiometer. Therefore, my question is: Does the instrument cluster control unit simply set temperature values below 30 degrees to 30 degrees, and is the sensor therefore functioning correctly?'

Regarding the coolant level sensor in the expansion tank: I performed a DC resistance measurement on the sensor. When the water/engine was cold (approximately 10 degrees Celsius), the sensor's resistance was so high that I couldn't measure it (>20 Megohms). At approximately 80 degrees Celsius coolant temperature, the resistance was around 50-100 kOhms (fluctuating).
I then connected an 80kOhm resistor to the connector of this sensor, but as a result, the coolant light still blinked. Is this sensor broken?

Was noch komisch ist: Mit abgezogenem G62/G2 Stecker konnte ich im MSG eine Fehlermeldung erzeugen. Dieses gelang mir im KI Steuergerät aber NICHT???? Auch bei abgezogenem Stecker des Kühlmittelstandssensors war keine Fehlermeldung vorhanden??? IIs that normal?

Regards,

Jens.