Howdy, I've been around cars for awhile but recently moved to California and bought a 2015 Prius 1 and a 2013 Highlander Hybrid. Both have been rolling for a few thousand miles with no issue getting close to their sticker mileage in the Sierra Nevada mountains. Until... both now have minor issues that do not seem to be affecting nikeage or performance for this post I will focus on the 2015 prius. It is throwing code p0403. Ive read this is in regards to the egr system, likely electrical. I have checked the efi#2 fuse, it is good I have checked the ohm readings on the valve motor, all read between 20.3 and 20.7 ohms. I appear to be gett8ng at least 11.64 volts from all the pins. I have park the car till I can get this resolved. Is the next step to pull the parts and prepare the brake cleaner for the egr valve, the egr tube and possibly the egr cooler?
You are on the right track with your electrical tests. I would probably repeat them and then ohm out the egr to ecm wires. With Techstream you could try the egr step test as well which measures changes in intake pressure as the valve opens and closes. However with that code its most likely not moving and the system can detect an electrical issue like an open or short.
