Hi. My car was just fine. But one day, i decided to go to a mechanic to clean the EGR pipe. Only the pipe, not the whole EGR. It was an extremely simple operation a mechanical one, not electrical etc... Starting from that day, when i go with the car, from time to time, check engine lights up. For a fraction of a second to up to 2 seconds....then it dissapear. The car behave itself without a problem. But still the on-off check engine is really annoying. So a went to the dealer. Put the car on tester. Result: no code error !!!! I went to another garage , put another tester on the car..... no error.... How is this possible ? How can i actually see what the error is if nothing is stocked in the ecu of the car??? Any of you ever encountered that ? My car is a Prius Plus 2012.
it's a long shot, but have you checked oil level? if not that i would reset the ECU by 12V battery disconnect.
There's an electrical connector at the intake manifold end of that EGR pipe, that has to come off before you can get one of the pipe flange bolts. Maybe something partially haywire with it now? Just a guess.