Maybe I could measure across the plug. I'm assuming 12v at one terminal and the other terminal is the signal back. Whether or not it's a set value from conductivity or any value above............?
E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
You need to do some wiring checks and check the coolant level switch for correct operation. It also has a correlation with the washer fluid level sensor.
2003 W209 CLK, 2005 R171 SLK, Volvo XC40 P8 Twin Motor Pro EV
On our W209 this message was triggered by a faulty fan/controller. Not sure if it's applicable to yours but it's from the same era so may be worth checking it out. We had also tried replacing the sensors first
You need to do some wiring checks and check the coolant level switch for correct operation. It also has a correlation with the washer fluid level sensor.
It could be. We tried both of those with our 209 but it was actually a faulty fan. Diagnosed and fixed by Prestige Car Service (Black C55). Worth checking just in case.