Throttle Body Cleaning at 15,000 miles?

It's throttle body cleaning.

Here's my story about the local "service" department.

I also was told on my last visit that my throttle body needed cleaning. I told them I'll take care of it later and declined.

Didn't have anything done to the throttle body. Brought it in for my next service. No mention whatsoever about a dirty throttle body.

Go figure...

SCH-I535

 

Dont trust dealerships on scheduled maintenance. I would say you wasted a lot of money. Filters can be bought online for $15 and take one or two minutes to put in. Throttle body cleaning = rip off! IMO. Your mileage may vary.

 

No that's not too bad to learn a lesson. Cheap lesson!

Like most modern cars the TB can get really sooty. Its important the throttle body on a Prius is maintained as its really expensive to replace as it has an integrated motor. Its fly by wire no throttle cable like most cars. Like around $1500 to replace. Doesn't take much to corrode the edge of the butterfly and then the motor can't open the butterfly.
There's literally hundreds of posts about TB issues on this forum. I clean mine every 15-20,ooo miles and it needs it.
Its very easy to clean and very cheap to do it. If interested pm me and I'll be happy to help you.

In the future before you go to the dealer post here about what you want done and we will help you save some big $$$. The very best part about a Prius is its low maintenance cost but there are some issues that will get you.

Btw, WELCOME!!

 

Julie,
When you say "I guess the correct thing to do is to drive conservatively"


Does that mean slow, while looking at the display that makes you want to drive even slower?

Some Prius drivers make a bad name for the rest of the Prius owners that drive NORMALLY.

 

Nice !

Watching and anticipating stop lights is a big one. Long regens are better than short hard regens.

 

If you run top tier gas I highly doubt the throttle body would need cleaning anywhere near 15k. More like 100k.

 

There's a lot of easy stuff in the owner's manual, check it out. You might also consider finding a different dealer to patronize.

 

This thread begs the question as to what contaminates a throttle body. EGR ports are typically downstream of throttle (please correct me if this is not the case for the Prius). But crankcase ventilation ports are typically upstream and this can be the culprit. But even with vehicles that consume some oil, I've only had to clean a throttle body at perhaps 100K mile intervals. But Prius vehicles don't often consume oil?

 

The Toyota Owners Manual doesn't cover basic maintenance, something like an oil change, for example. Coming from about 30 years of Honda ownership, I think their Owners Manuals have always had an oil change description, and continue to do so.

The Honda Service Manual is much more attainable too. There's a mention of it in back of Owners Manual: it's typically a 1.5"~2" thick tome, fairly well organized. You have to hunt a bit for the basic maintenance items, they're not all rounded up at the beginning. But it's fairly readable. The main negative: like everything these days, the more recent manuals are awash in esoteric acronyms. It's about $100, not bad.

The Toyota Repair Manual is another story though: multiple volumes, unjustifiable price for the DIY'r, and hopelessly terse/unfriendly. There's a pdf available (sporadically) on the net. I would look for that. It'll deter you from ever wanting to buy the paper version, when you see it's format, LOL.

We went to a "new Toyota owners) open night, put on by our dealership. It was a little dismaying to hear the Service Manager saying that owners should never have to or need to pop the hood.

 

I agree and cleaned my Caddy's TB and TB plate almost yearly and it wasn't too tough of a job. It meant taking off the air intake and then one more component to get access to the TB and plate. Even using better gas, there is soot in the TB and a bit of gunk that develops on the plate or "butterfly" valve. Since the Prius is "fly by wire", could you share with me (and members here) how to gain access to the plate? I have seen on the repair manual that it is under the air intake but have no idea how to safely open the butterfly valve for cleaning. Thanks in advance for this info.

 

Prius gets pretty sooty from PVC crankcase vapors and uses a brass butterfly plate which is very susceptible to edge corrosion. That's an issue because unlike a normal car that has a throttle cable if the butterfly gets a little grabby from the edge sticking you just push the pedal harder and you may never even notice the butterfly is hanging up. In a Prius its motor controlled so you don't have any tactile feel about the pedal/butterfly smoothness. Not sure how grabby it has to get before the tb motor struggles to open it but I don't really want to find out.


Given that the Prius TB motor/butterfly assy is a non serviceable component and must be replaced as a unit and very expensive it behooves an owner to look at it every 15k and if any edge corrosion is forming clean it.

There two 10 mm bolts on the top of the air cleaner box. Remove the big hose clamp for the air intake. There's a throat clamp below the air cleaner box that keeps the box tight to the tb
throat. Thats a 10mm bolt and need extension to reach it iirc. Air box will come off but maf sensor connector is still on the ac box. It's easily removed by pressing the clip and pulling the connector off.
Maf stays on box you just remove its wire. Ac box will be free set it aside..

Remove PVC black hose from back of TB.
Rotate the spring on the left that opens and closes the bf (butterfly). Cut up old t shirt into 2 inch wide real long strips. While holding the butterfly open by the spring shove a strip all the way down as far as you can to the bottom of the tb. Don't use a screwdriver or anything metal to shove it in as it may scratch the bore. With strip installed soak it with spray carb cleaner. Wearing nitrile gloves and holding the bf open scrub the walls and butterfly best you can with the wet strip. Pull out filthy strip. Tb will be dry and clean. Repeat with a fresh strip till no more dirt on strips. Also while strip in there flush out the pvc pipe connection the pvc hose is hooked to.
Spray lube the bf spring.

Put ac box back on don't forget underside throat clamp.

Whats gas quality got to do with it?

 

I agree with this observation -- gasoline not present at throttle body. But it makes me think about the quasi Atkinson cycle, i.e., keeping the intake valves open at the start of the compression stroke. So, do some gases from within the cylinders gas "snorted" back into the intake manifold?

 

Yes I bet it does as it gets pretty sooty. And there's also the tiny puddle of oil at the bottom of the tb too that's disconcerting at first but always there.

Its a whacky little motor.

 

Thanks edthefox5...I put this in my notes for future reference. I'll probably do this maintenance sometime this autumn.

 

My pleasure.

If you really want to preserve the TB its best to bypass the coolant loop that is hooked to the tb to keep it warm.
This little mod is not suggested for northern folks as your tb will freeze up in the winter but for us flat landers down here it really helps.

The 2 little hoses in the bottom front of the tb one on the left one on the right is ICE coolant circulated through the tb body. Its used to keep the tb warm in the winter but totally unnecessary in summer or southern cars. It just puts enormous heat stress on the tb motor.

Using a 3/8 PEX barrel found at Lowes just pull the 2 hoses off and barrel them together with hose clamps.
Now instead of the TB temp at 190F it will now be around 90F a 100 degree difference. Its pretty easy and you will only lose a very small amount of ICE coolant doing this. Top off the ICE reservoir. Not even a quarter of a cup.

This is an old hot rod mod. Cooler the TB the better the performance but hard to tell any performance increase
on this particular car.

There training there customers to not open the hood. Which makes the owner scared of the car and thinks the only people who can work on this space ship is the dealer. We see it here all the time. MFD and dash lit up like a Christmas tree. People go to the trouble of joining and posting here before they even open the hood on the car and check the fluids. Its crazy.

Which is to bad as its a normal engine under the hood and like any other car requires a fluid inspection upon every fill up. Especially a Gen II with 100+ miles on it as they start losing oil.

 

Is this true for Gen 3?

 

True for all cars. Heated only so TB does not freeze from frozen air being sucked in the TB in winter.

Heated TB very unnecessary in southern states. On some higher performance cars you get a little performance benefit as the intake air is cooler.

First thing I did to my Prius after I bought it. That was 6 years ago. Couple of winters here it went down to maybe a terrifying 40F lol and no issues but forget it up north. The TB would freeze up fast.