I have a 2012 Toyota Yaris LE Hatchback with 107,000 miles. Most parts are interchangeable with the Corolla, Scion, Prius, etc so this may be an overall problem a lot of people are having and hopefully you can help me with it?
I bought it used and it shook like crazy so I replaced pretty much everything on it so it runs great overall, but nearly every single day the check engine light comes on for the same couple of problems, despite pretty much all of the related components having been replaced.
I've also noticed it is also related to temperature and every time there is a big change in temp I know I'll have to remove the check engine light again upon first startup for the day. It has come to the point that I keep an OBDII scan tool in my car bag to reset it on a regular basis.
Oddly enough it does run great. The thing can move out but every now and again when that check engine light pops on it can get a light stuttering like it wants to stall at a stop light. Comes and goes. Some days the check engine light doesn't even pop on, some days it pops on but there is no noticeable change in air/fuel mixture from the driver's seat, other days it shakes.
I am getting the following codes regularly:
PO441 EVAP System Incorrect Purge Flow
PO455 EVAP System Leak Detected - Large Leak
I have changed all spark plugs, coils, oxygen sensors, intake and overall vacuum system gaskets, , canister purge valve (granted with a cheapo refurb and not brand new $100 one, would you recommend the brand new?), vacuum lines/hoses, fuel pump, injectors, (brakes), (struts), the ECM itself as well (with zero change in codes at the time BTW and zero change in behavior, as if I never changed the ECM, so I could strike that off of my list, LOL), oil and filters are good and are changed, changed transmission filter and change trans oil, coolant is changed and changed when needed regularly, replaced the VVT solenoid and cleaned the filter, replaced PCV valve, intake, throttle body, MAF sensor, (thermostat - upgraded to lower 180 degree with no change in behavior), New belt, Upgraded the alternator to 150 amp with no change in behavior, New battery and posts - optima yellow top, All new grounding screws and in some cases cables - no change in behavior, new gas cap - basically vacuum system/lines and I've replaced even more that I'm just not remembering at the moment.
I won't just say no change in behavior because I'm getting a little better on the MPG and it certainly drives smoother/nicer/better with each change/upgrade, but the same light and codes still pop up!
Water pump is tight but will still technically have to replace that sometime or another LOL
I do however still have an ABS light on and have to change the rear magnets and front speed sensors/magnets,
also never replaced motor mounts but the shaking stopped since then and the codes/behavior I'm getting is likely not involved(?).
But in the meantime I would like your input because I think it either has to be retrained to idle properly, which I have no idea how to do or I just have to keep replacing parts until it stops I guess?
I would appreciate any help you may have on this.
BTW, Love your show and think you're a great person for putting so much experience and information out there like you have. Have learned so much from you and really appreciate it Scotty! Thanks so much for all you do!
If you can't find a leak in the EVAP system then smoke test it.
You have a large leak code. Smoke will pour out of the leak location. With that code I'd suspect the vent valve isn't seating properly when closed or its gasket seal to the canister is faulty. Then again, it could be something like a failed gasket where the fuel pump mounts onto the tank that's leaking a little. A smoke test would find that too.
You can also do a smoke test on the rest of the vacuum system to check for leaks in it.
https://www.youtube.com/c/ScottyKilmermechanic/search?query=evap
Your EVAP system needs to be diagnosed properly, rather than parts thrown at it. It should be tested for leaks, and proper valve operation needs to be verified. The refurb unit may very well be a dud. If you diagnose, you can save money you spent on useless parts, and put it towards good quality parts instead.
Firing the parts gun at a problem is just asking for disappointment.
I have already had it looked at by 2 mechanics. One was stumped and thought it was the oxygen sensor, the other said to just change out all of my vacuum lines since they were somewhat old. I did both and no change. I also tested for leaks using 3 different methods and found none, the intake manifold is fine but of course the gaskets get old so I replaced that and the throttle body gasket when replacing the throttle body and still no change.
Yes I understand throwing parts randomly is normally stupid, but not in this case. In each case the part was in need of replacement so it doesn't exactly hurt to just go ahead and do that in the hope that it's the right part. The only 2 cases where it was a gamble but still useful were the ECM, but even then it was rotted on the exterior and shortly in need of replacement anyway and the purge solenoid, but since it's at about 100K that couldn't exactly hurt either, but also had zero change in behavior showing my current refurb is either just as old as the previous or that it's not the problem.
Tried taking it to a 3rd mechanic but that made it all too clear to me that mechanics don't know as much as they used to since he had a hard time with even the most basic car knowledge so I'm steering further away from that now and hoping to get some experience or knowledge behind this or it's looking like it's not going to happen and I'll just have to reset my CEL daily LOL Oh well.
Thanks for the link.