NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10

Maybe that's why folks who've been married a long time have a golden anniversary and then a diamond one. They get denser in their old age, too.

 

I don't know... considering the conditions that this issue prevails in... what is hard to believe is that they can't fix it now that they know about it.

 

I would agree!

 

Mine did the shake the other day. I moved my car in the morning when it was about 15 degrees out. No shake. Then a few hours later, I started it up and it shook like it was falling apart. Turned off and opened the hood to make sure no critter was in the fan area. (don't think it is possible) but then started up with no problem.

 

First time this happened to me today after it sit for 6 days in the garage. Sounded like it was going to blow not just knock. Should I tell the dealership or not? I have 2013

SPH-L710 ?

 

Yes!! Tell them as a matter of record, that you did report it.

 

Funny - 1st time I ever saw a PriusChat item posted in Russki.

 

I own a 2011 Gen3 (very low miles) and a 2013 Prius C (also low miles). Haven't had the problem so can't say from experience how it sounds or what it might be. However, if the car is shut down while the engine is in the initial part of the warmup, it's running on rich mixture. If ignition goes off before all fuel in the intake system is burned, that fuel remains in the intake manifold or cylinder ports and can cause a misfire on the next start-up because there is excess fuel entering the cylinders and the mixture is too rich. That's why opening the throttle when the roughness occurs tends to make the engine smooth out. It has the effect of quickly leaning-out the mixture so the cylinders have proper fuel/air ratio. Roughness could be a momentary misfire due to excessively rich mixture. If so, even repeated occurrences would not harm to the engine - which seems to be the case. I'm not that knowledgeable about the Prius or Atkinson cycle - so it's just my conjecture.

 

Update: it's been to the dealer three times since I made this post. On this last trip, the dealer was finally able to recreate the noise and a Toyota engineering team is now evaluating the car. The knocking has actually become more common even with the warm weather streak that occurred in the Mid-Atlantic during mid-October.

Giving the Toyota dealership the technical service bulletin listed has helped immensely. Switching service managers to one that actually takes this issue seriously has also been useful, but like many others, I have no loaner car during this time period. I'm most likely trading the car in for something more fun whenever I get the car back, as this really is not what I wanted out of my Prius experience. My 2010 is at 24,72x miles, so I'm hoping to get this resolved before my CPO warranty expires.

Annoyingly, there are 5 other Prius models in the family, ranging from 2011-2014 model years, and while all of them have more mileage, none of them exhibit this issue.

 

Yesterday was a 40+° day and my wife and I were out and came home around 1:30 p.p. I left the car in the driveway while I took Christmas lights down. About three hours later, 4:30 - 5:00 p.m., I pulled the car into the garage for the night. This morning , when my wife started the car to go to work, rough engine noise, this time only 2 - 3 seconds. I thought it would happen so I filmed it. Still waiting for Jeff Wyler Toyota to call me after my service guy was to talk to the Service Manager. That was on Friday, December 20th, when I just stopped in. Nor have I heard any more from Toyota USA. btw, did I read some where the Lexus hybrid with the same 1.8 engine has the same problem?

 

The Lexus ct200h has the same problem and a TSB has been issue just like the one for us.

It also includes the same condition that it must be reproducible at the dealership.
Here's a link to a post.

 

I purchased a used Toyota Prius last year. It has 87K miles. Last winter sometime, it started really rough and loud. It happened twice.

Yesterday it happened, but it didn't seem as loud. This time the check engine light came on, so I didn't drive it. I turned it off immediately.

Toyota wants to replace the Intake manifold for $750 (that includes the $120 to read the code). We can't afford it right now.

Has anyone determined if it will hurt the car to clear the check engine light, and hope it doesn't happen again? If leaving it won't cause any more damage then I'd rather take my chances and try the prevention methods listed later in this thread.

Thanks for any help you can give me.

 

It will not hurt to clear the light and drive it. It sounds much worse than it is. It happens most often after a short start cycle, when the ICE starts and then stops before completing the warmup cycle. When moving from driveway to garage, for example.

It happened to me twice this way in my first year. I have learned to always let the ICE complete the warmup cycle and have not had a re-occurrence since.

If it happens again, floor the accelerator and it will quit the knocking.

 

There is no fix for the issue, yet. So save the money for now.

Toyota has made attempts at different intake manifolds but some say the new part# still produces the issue at certain conditions.

Even the newer cars are still seeing the cold start issue. So that tells you the newest part number Toyota must be using for the manifold is not working.

This site has generated some suggestions to help avoid it.
These suggestions are based on individual experiences, YMMV.

 

Out of curiosity, what is the difference between the 1.5L and 1.8L (I know, 300 cc) in so much that the smaller engine doesn't seem to have the same problem? Is the IM made out of different material, different gaskets, anything?

 

i don't know but i wouldbet the gen 2 is alloy and of course the 3 is plastic.

 

We have a 2010 Prius which I purchased new in May 2009. I believe my Vin falls in the vehicles
subject to this problem. We now have over 110,000 miles and because we live in Oregon I am
still covered under warranty. I have not noticed the engine running rough when cold and the
check engine lights as not come on but still would like to get the fix for future proofing....

 

alfon...the "intake" T-SB has not solved any problems yet, but I would get the one for the engine mount done as the burden for replication is less. No telling what that will cost after warranty.

 

I believe the new IM TSB only falls under a 36K or 60K mile warranty. It says in the TSB.

 

I just want to add my experience here.

I took my prius in for this repair today but they said that while they know of the problem, they won't fix it unless the check engine light is illuminated. Sounds like bullox to me.

The story of how I experienced this behavior was somewhat interesting though. I bought my 2010 prius from an Acura dealer 2 days ago and the very first time I fired it up it made this intense shaking and knocking, as described in this thread. The sales rep told me not to worry about it and that it happens often to cold cars. But I've driven plenty of cold cars and none sounded like they would explode like that. Anyhow, so I drove it around the block and everything was perfect but I told the guy I wouldn't buy because of that sound. Well, after continuously lowering the price he convinced me and was very glad to find this issue on this forum and learn it's nothing to be alarmed about.

I got an immaculate 2010 prius III with leather and 48k miles for $17,000 out the door. That's about 1.8k under bluebook. Happy customer here! Probably helped also that it was Dec 31, the very last day of the year and month.

Hopefully the dealer will start fixing this problem without the check engine light coming on. Living in southern california I have very little chance of recreating this in front of the dealer.