2006 Prius w/125k mi. My car has an intermittent problem. While driving at 30-45 mph, the engine just stops and the dash lights go off, for no apparent reason but, immediately after coasting to a stop, I was able to restart it with no indication that it had ever stopped. I've had this exact experience with the car 3 times within 5 days. Each time around 30-45 mph. Engine was not running too hot. There was no loss of engine coolant. There were no loose battery connections. There were no – warning lights and the OBD II showed no codes. Both batteries had a good charge. each time I was able to immediately restart the car after coming to a stop. This happened two months ago, over 2000 miles back but hasn't happened since then. I plan on doing a long out-of-town trip and am worried that I may not have the same good fortune of an immediate start up or that I may be in a dangerous situation at the time the engine dies. Toyota says they "cannot find anything abnormal with the car"! I know Toyotas are well engineered but, I have a hard time believing they can fixed their self.
pretty tough to diagnose something that happened a long time ago, and didn't throw any codes. maybe a loose connection somewhere. for long trips, you may want to think about a rental, or upgrading to a newer vehicle.
I would want to know if all the power was off when the episode occurred. As in no radio, no fan, no dome light, no MFD. Or was it just the odometer/speedometer/dash lights. If it is the latter then perhaps it is a combo meter issue? If it is he former then maybe a wiring or ground issue? Intermittent problems are hard to track down. Would be better if you could reproduce it at will. (for example left turns over 35)
Engine ECU, or fusebox problem maybe? Camshaft/crankshaft sensors, or even any of the SMR(system main relays), could act up.
