I solved the problem of calibrating the engine probe. On the connectors of the hall sensors, I connected an 18kOhms potentiometer between the white wire and the black wire in parallel with the probe. I set it to 15kOhms. I used an online calculator to determine the value of the potentiometer.
https://www.digikey.fr/fr/resources/conversion-calculators/conversion-calculator-parallel-and-series-resistor
Now it's possible to calibrate the probe. At 0ohm+probe=32°c to 18kOhms+probe= 10°c. This indicated a fair value as you can see in the photos. Before modification the probe indicated 32°c instead of 18°c now.
https://www.digikey.fr/fr/resources/conversion-calculators/conversion-calculator-parallel-and-series-resistor
Now it's possible to calibrate the probe. At 0ohm+probe=32°c to 18kOhms+probe= 10°c. This indicated a fair value as you can see in the photos. Before modification the probe indicated 32°c instead of 18°c now.