Please keep us posted to let us know what caused this to happen and what’s broken on your Sienna.

 

We clearly have more than a software issue on our hands.

Might be simpler. Consider checking charge level in the 12V battery in back. Root cause of many weird gremlins and super common in winter for batteries to deplete quickly.

 

Will need to scan for codes to start

 

Have you ever clean/replace the filters located under the driver and front passenger seats? Those filters are essential to keep your hybrid battery from overheating.

 

You are correct in saying that this [sloppily designed] filter is essential for helping the battery stay at optimal temperatures, but I don't believe a clogged filter would cause the whole hybrid system to shut down. In my Prius, which I no longer have, I did have my battery cooling air filter clogged, but the only symptom I had was the ICE not shutting down as often as normal during low speed driving.

 

A follow up would be greatly appreciated. Most people report and ask the about an issue they encounter and never follow up with a conclusion/resolution. I have faith in you @Alabama XL40

I’m in the market for an extended warranty. I reached out to Jerry at Midwest. My 23 is 2.1 years in at 30k. I estimate reaching 36k this Aug.

 

You are in California, right? Jerry is not dealing with California. If he does, I like him a lot. Good guy and deserves the business.

Somebody over in the 4Runner forums complained loudly he couldn't get the rates that Jerry was offering at a California dealership. After that, according to somebody who worked at Toyota corporate and a regional person I happen to know, the vehicle service agreement people were told not to sell to California, I also heard that they were told not to sell to Oregon or Washington either. The refusal to sell is under the guise that it's about insurance, because that's what a vehicle service agreement is. California is anal about insurance sales so much so that most companies don't want to do business here any longer.

I have talked to a dealership in Southern Oregon who would sell to a California customer. I have an out-of-state mailing address through my management who is willing to accept my mail.

I found it interesting that, no matter what the trim was, the prices were the same.

@Sienna.Guy, I trust you wouldn't go in and argue with a dealership, if you want to DM me, I can send you the info as given to me. I'm pretty sure that the guy has been mentioned on these pages, possibly mentioned on the 4Runner pages. Not absolutely sure. I owe you that much. After watching the spare tire kit installation, I insisted that my new car on order have the spare tire for all $75 of it.

 

Just got back into town today.

The diagnosis was a fouled spark plug cylinder 3 causing a misfire. The misfire then sent the hybrid system into limp mode, and gave off a whole bunch of other codes including sonar system failure, etc. Spark plug replaced and codes cleared. Vehicle drives normally.

Will be following up with my usual mechanic tomorrow to investigate further as to the cause of the spark plug fouling. I hope we don’t have a buildup issue from incomplete combustion or a valve leak or etc. But I’ll keep y’all updated.

Thanks for the other suggestions. They may be helpful for anyone who stumbles across this thread.

 

Another thought... Head gasket failure in the future? A block test might be in order.

 

What brand of fuel & octane, and brand of oil, variety (Advanced, Extended Protection, etc) & SAE grade?

 

Pretty exclusively Texaco/Chevron regular fuel (octane 87) and up to this point every oil change has been done by Toyota with Toyota branded oil at the manufacturer spec. We have changed oil every 5k miles.

 

Looks like plugs need to be replaced around 60k miles

 

Interesting the plugs fouled on a modern vehicle so quickly. Something else must be going on. I used to change spark plugs on my older vehicles on a regular basis, but these modern vehicles are something else. My 99 Chevy pickup went 150,000 miles before changing spark plugs that didn't need replacing. The gap was still good and there was no discoloring to any of the spark plugs. I wonder how hard the turning on and off of the hybrid gas engine is on spark plugs?

 

I am with you on this. There may be an underlying problem there. I don't think spark plugs are due until 120K+ miles, from any anecdotal experience.

I haven't done spark plugs changing since the 1990s, literally. In the past 25 or so years I have driven quite a few vehicles past 70K miles and the spark plugs didn't need any work or replacement.

Leased 2008 Escape, 2010 F-150, 2013 Explorer
Owned 2014 Prius (that went all the way to 131K miles) and now 2021 Sienna @112K mi, which has had all kinds of annoying booboos, but not the spark plugs.

 

It’s not that. The engine has new tech called direct fuel injection where the fuel injector is inside the combustion chamber instead of before the valves. Carbon builds up in the plugs. Now what I’m wondering if this engine also has similar tech to the frs and gr86 where they also have port fuel injection to compliment the high pressure fuel injectors to reduce carbon build up.

 

It’s not that. The engine has new tech called direct fuel injection where the fuel injector is inside the combustion chamber instead of before the valve. Carbon builds up in the plugs. Now what I’m wondering if this engine also has similar tech to the frs and gr86 where they also have port fuel injection to compliment the high pressure fuel injectors to reduce carbon build up.

Yes, the engine has port fuel injection. The direct injection is primarily used during warmup and is a bit noisy. Port fuel injection is used in normal operation mode.

 

Then how to mitigate this; by checking spark plugs for carbon build up more frequently? And/or changing them sooner than later?

 

That’s crazy going that long without replacing plugs. You should do them sooner than late as the threads can seize onto the head and may need extraction. Worse case scenario it can’t be tapped so you end up needing a cylinder head

 

We got our money worth already, it's a bonus that the van still runs. At this point I really don't care, if the van dies so be it.

 

What measures were taken during new car break-in? Any trips taken during that time? How long was the drive from the dealership to get it home?

Seal quality (gaskets, o-rings, sealant, piston rings, etc.) is greatly impacted by many factors during its break-in period.

Also, when was the first oil change performed?

As an aside, there were a lot of finish quality issues with this generation of Sienna. Slowing down the production line to help mitigate some of the problems.... That's why it takes months to get a Sienna nowadays.

 

As an aside, there were a lot of finish quality issues with this generation of Sienna. Slowing down the production line to help mitigate some of the problems.... That's why it takes months to get a Sienna nowadays.

Citation please.

 

Thanks for the information. That confirmed it does have port and direct injection