Chances are your resevoir sensor is bad. You can fix that for free by doing what this guy did. I had the same code pop up 2.5 years ago, right as my kid was born, and this trick fixed it. No coolant codes since then.
Coolant Sensor “Temp” Fix with NO CEL on
Hopefully this will help one of you! Just hit 34,000 on 2019 Cummins, driving home, check engine light came on, followed by “reduced engine power warning”, pulled over, scanned OBDII, and got code P00B7 (coolant level too low). 1) checked coolant level and it was at the correct level 2) pulled...