> My last car had the check engine light on from years 3 to 15, when I sold it. The reason was a faulty sensor but the actual mechanics were sound Some Nissan

> My last car had the check engine light on from years 3 to 15, when I sold it. The reason was a faulty sensor but the actual mechanics were sound Some Nissan models used to have a fun version of this where the check engine light came on to notify you about a problem with... the check engine light. It was a bug, obviously, but not a sensor wrongly detecting a fault. Rather, the car's only way of saying "if something goes wrong the check engine light might not activate" was to activate the check engine light. Whatever the underlying issue, I assume software, replacing sensors didn't work and resetting the light would only last for a few hundred miles. It was effectively impossible to keep the light working, so the mechanic-recommended fix was to just disable it.