Been a lurker for a while but I'm nearing my wits end on this project and figured it was time to ask the experts! I picked up a 2010 Prius for a very low price a few months ago (sub $1000). When I first went to see it I was surprised to see it ran and drove, the a/c worked, etc.. The only issue other than cosmetics is that car would like shake rather violently when the gasoline engine kicked on at low RPMs, give it some more gas and it smoothed out. He had a print out from where a local Toyota dealer looked at it a week before and they said the problem was the EGR, and he was selling because they quoted him more than $1000 to fix it. I checked here before committing and saw this was indeed a common problem with this generation, and the misfiring was a symptom of that, so I felt reasonably confident in their assessment. I bought the car and ordered a used EGR off eBay that at least looked good, don't know the mileage of the car it came off of but I made sure to clean it thoroughly with brake cleaner and the same brushes linked in the very informative NutsAboutBoltz videos, made sure I could see through the other side so it wasn't clogged (I cleaned out the hard pipe to the intake as well).. I swapped it on and no change, still shaking and misfiring. The previous owner said he put in new spark plugs but I figured who knows, so I bought new ones again.. No change. I take it to get the code run at AutoZone and it says this: P0303 - Cyclinder 3 misfire detected P0304 - Cylinder 4 misfire detected P0102 - Mass or volume air flow A circuit low input P0113 - Intake air temperature sensor 1 circuit high input P0123 - Throttle / Pedal position sensor A circuit high input After this I pull off the intake manifold and clean it out too, replaced it with a brand new intake manifold gasket. I sprayed some MAF cleaner on the air sensor and wasn't sure how to tackle the throttle code so bought another used throttle body (because I think I read the sensor in it isn't removable)... Still nothing. Probably unrelated to the problem but I put a new 12v battery in it because I killed the old one from letting it sit a couple weeks. What else can I try?
Welcome to Prius Chat . Some questions: How many miles on your Prius? Is the engine coolant level stable? Is there white smoke coming out of the tail pipe when it runs? What does the oil look and smell like? You didn’t think a sub $1k car would be an easy repair I hope? My bet is that all the low hanging fruit has been addressed and what your left with is a failed head gasket and a clogged egr circuit. Good luck and keep us posted .
I am wondering why the OP has reported P0102 and P0113, which both relate to the mass air flow sensor (as the air temp sensor is also within the MAF assembly) and also P0123 which shows that one of the throttle sensors, VTA1, is producing greater voltage than expected. Those don't seem to be related to a clogged EGR or a blown head gasket... Since he's already replaced many parts I would suggest that he obtain the repair manual info at techinfo.toyota.com and follow the troubleshooting for those three DTC. Maybe he will find that faulty wiring is part of the car's problem.
It has a ton of miles, something like 330,000.. I'll have to double check. I leave it sitting with the battery off for weeks at a time and never drive it for anything other that testing purposes but I've never noticed it emitting any kind of smoke. I've added coolant to it because I dumped out a good bit removing the EGR and throttle body, can't say if it's using any or not. I've been leaning more toward an electrical sensor sort of issue because when I first reconnect the battery (which clears all codes), I drive it around for five, ten minutes or more and notice no issues at all. I know there's a whole dance involved to forcing the car to use the engine which I haven't bothered with, I've just put it in Power mode to try and make it use the engine more. it seems to kick over and work fine until the ECU runs through a few cycles and then eventually before long it starts to stumble, then the check engine light comes back on and that's the way it stays.
I bet this one dropped a valve. I got the p0102 and p0113 when the intake valve was leaking on my reassembled motor. I’d venture to guess at idle after a few seconds the engine stops responding to accelerator input too.
