Yesterday, driving home. My Prius started shaking violently. It felt like the front wheel bolts were loose. I stopped the car and checked the wheels, and everything seemed to be tight. I drove on home and noticed the check engine light was blinking. Furthermore, I noticed that the shaking would start and stop at different speeds. When I got home, I put a code reader on it and got a 7E8 and 7EA codes. I read up on the codes, but none of them seemed to fit the problem. This morning, I started up the car and the engine was running like an unbalanced washing machine on spin cycle. So, I shut it off immediately. It was pretty much the same shaking experienced yesterday, but the car was sitting still. Any thoughts as to what might be the problem? The car is a 2010, with 190K miles.
That usually indicates a severe misfire. I've never heard of the codes you got. What sort of reader? Many code readers don't know how to ask a Prius for full details, so they only give part of the story.
Yes, a blinking CEL is only triggered for a serious misfire. Usually ends up being due to a bad sparkplug, but there's obviously several other possibilities, especially with a Gen 3. Could be as simple as a bad plug, a vacuum leak, or the dreaded failed head gasket.
You're at the right mileage for everything to be going wrong The thing to do with this model was to be out of it by 1:50 160,000 mi somewhere right around there and you would have been golden. It's just an unfortunate thing
Have you had it since new? If not, what was the miles when you bought it? EGR and Intake manifold ever cleaned?
7E8 and 7EA are not trouble codes. They are being reported by the scantool to tell you which ECU is reporting the trouble codes. Trouble codes are 5 digits in length for a Gen 3. For example, P0301 is the trouble code for a misfire in cylinder #1. How long have you owned the car?
Sounds to me like a case of reading the wrong things off the reader's screen as the codes. Three-hexdigit things like 7E8 or 7EA look to me like the CAN addresses of the ECUs that are reporting the codes. That's useful information to have, so a code reader that shows those is more useful than one that doesn't. (That said, I seem not to have memorized which ECUs have the addresses 7E8 and 7EA.) But the reader should also have shown the trouble codes. Trouble codes are five characters, where the first one is always P, C, B, or U, the next one is always 0, 1, 2, or 3, and the remaining three are hexdigits. Were there some things shown that looked like that? Edit: beaten to it by Brian1954!
Thanks for all the quick responses. The reader is an Autel MaxiScan MS 309. It has worked on previous problems, but it's not Prius specific. We have had the car since new, and it has been a pretty good car. I bought my wife a new car 3 years ago, and they would only offer me 3 grand in trade. It was working well at the time, so I figured I'd keep it till it quit running. I guess I'm getting close to that now. If it is something I can fix, I'd like to keep it. It still gets 40-50mpg. But I don't plan to sink a bunch of cash on it. I am retired and do most of my own mechanic work. I can handle just about anything mechanical, but the electrical/computer stuff is beyond my ken. Is there a good low budget Prius friendly code reader? For the past couple of months, the check engine light would come on and the next day it would self cancel. It just passed state inspection last week, and they warned me that the rear bake pads are due for a change. Thanks again
The problem in your earlier post is that you copied down the ECU addresses it was showing you, not the codes it was showing you. We need the codes. A code is five characters in length, starts with a P, C, B, or U. The reader has gotta be showing you that, just somewhere else on the screen; that format is nothing Prius-specific.
I dug a little deeper First thing I noticed when I turned on the ignition was the message on the dash display, "Check Hybrid System" New error codes P0300- Random/Multiple cylinder Misfires detected P0301- Cylinder 1 Misfire detected P0303 " 3 " " P0304 " 4 " " P3190 Manufacturer Control Hopefully this is the info you needed. It doesn't mean much to me yet, other than it must be running on one cylinder
Those codes mean severe misfires were recorded for cylinders 1, 3 and 4. They don't necessarily mean that those cylinders are always misfiring, but it is possible. Generally speaking you need at least two working cylinders to maintain an idle, and sometimes three. The P3190 code means that the computer was surprised by how little power the engine is producing given current conditions. So, really it's a technical confirmation of what we already knew from the blinking check-engine lamp: severe misfires. It doesn't tell us any more about the root cause. Still have to go back to the basics for that: fuel, air & spark. Given the sudden onset, I'd probably be looking for an air leak/hose popped off, maybe a broken ground strap on the head... something like that. Either way it's going to take detective work.
"Manufacturer Control" is what the scan tool says 'because it's a P3 code? Strictly speaking, I think the P0 and P2 codes are SAE standardized, P1 codes are manufacturer defined, and P3s are "jointly" defined. I have no idea how "jointly defined" was meant to work out in practice .... Yeah, in a Prius that specific "jointly defined" code turns out to mean that.
Thanks again guys for all the responses. As soon as the weather warms a bit, I will start troubleshooting to see if I can economically solve the problem
