The check coolant stop light keeps flashing on my O2 Volkswagen Pasan 1.7 turbo but the temperature gauge is not reading that it’s hot what do I do

Have you actually checked the coolant level? If the level is normal than the sensor probe is coated with sediment ,, it's a common problem on older cars due to deterioration of the hoses plus other things that accumulate inside the radiator over the years ... you can take it out to clean it if it's in an accessible area /// they are usually held in place with a clip ... when you pull it out expect to get a flood of coolant ... I cleaned mine but it soon was contaminated again so I just unplugged it and put a 10K resistor across the plug to keep the light off

thanks for share