P0128 encounter

This morning, I remote started my car to warm it up in the garage. I have a remote starter installed on the car. I had it on for 15 minutes which it timed out and the car shut off. About 10 minutes later, I went in to hop in my car about to reverse out. As I was backing up, I saw check engine light go on. My pioneer after-market head unit has a DTC reader indicating I received a P0128. I was dropping my kid off at school and decided to research when I got home. After some research, it appears that P0128 is when coolant temperatures did not reach a certain operating temp in a certain amount of time when I started up my car. I'm not sure if remote starting my car and not driving it is the cause. My pioneer head unit also has car gauge readings and specified my coolant temp. I reset the code to verify I can get it again. I test-drove to monitor my gauges. At first, temps started off at 40 degrees Celcius and slowly worked up to 80 degrees. Then it seemed to hover around 88 degrees, and the max went up to 92 degrees when I was going up a hill. It doesn't seem like I have a stuck open thermostat. Is it possible that it was intermittent? I don't appear to be getting the check engine light again.

 

i actually got the heat exchanger repaired per TSB roughly in 2020? Coolant level is good. A bit higher than full. dealership filled it to that level when i got the heat exchanger replaced, and i kept it to that level since. no apparent leaks anywhere that I can see, but bunch of plastic below the car doesn't let you see any drips that would have dropped on garage floor.

 

My car is 2019 and I only drive less than 10k miles a year. So I would consider a failing thermostat be fairly early for me. And I’m assuming that my head unit monitor status of coolant temp is reading the sensor which sounds like reasonable ballpark expectation in temps. Guess I’ll just monitor for handful of days and see if check engine light shows up again and verify temperature looks in range.

 

one other note I want to specify as a data point that I just realized, I did leave the car in the garage for 4 days undriven and when about to drive my kid to school, I warmed up the car for roughly 30 minutes (2 remote starts - 15 minutes each), and then got the DTC when backing up. curious whether there is some computer logic that is counting some timer of on time with the car and not reaching to a specific temp.