Re: Mass Air Flow Sensor & Throttle Body Service
 

What kind of miles on the car? Are you using K&N air filter (or other oiled media)? Is the CEL on?

With high miles (>60K, plus poor quality fuel), throttle body cleaning will help with idle stability. Cleaning out the idle air passages + throttle body is a good thing. Likewise, with high miles or over-oiled gauze filters, cleaning the MAF can help. For low to moderate mile engine, absent any drivabilty complaints, it's most likely a revenue generator for the dealer.

Re: Mass Air Flow Sensor & Throttle Body Service
 

I have 32,000 miles, Toyota air filter, no CEL. No drop in mileage or any symptoms reported by me. I think the dealer just wants some extra money.

Re: Mass Air Flow Sensor & Throttle Body Service
 

If it ain't broke don't fix it.

Re: Mass Air Flow Sensor & Throttle Body Service
 

The TCH does have Multi-Point Fuel Injection that's sequential. That's specifically for metering the fuel.

The TCH also has a Throttle Body (as do all fuel injected gasoline engines) that meters Air.

There are some trucks & cars that have an Integrated Throttle Body / Fuel Injector system. Those integrated systems have mostly gone by the wayside in favor of the more fuel efficient multi-point systems.

Hope that helps..

By the way - at 20k miles my AF Sensor (Air Fuel - according to the receipt) went out triggering the CEL.

Re: Mass Air Flow Sensor & Throttle Body Service
 

Well, i just got the same suggestion from my dealer at the 28,000 mile service...have had no problems and mileage on my 2008 Prius has stayed steady depending on how we drive it...35-48 mpg regularly. They quoted about $300.00! I declined...dealer is Koons Toyota of Annapolis if anybody else wants to know. Also wanted about $30 more for wiper inserts? Think I'll be doing the rest of my service elsewhere!

Re: Mass Air Flow Sensor & Throttle Body Service
 

Majority of the dealers do that (and other shops too) kind of recommendation. Unless you are experiencing a bad idle or check engine light shows up (with a code) then cleaning is necessary. Unfortunately the TCH doesn't have a tachometer to show you the fluctuations in RPM. If the engine runs fine it's not necessary and they are easy to clean. There's a MAF sensor cleaner and a Throttle Body cleaner available in auto parts store (and they are very cheap)

Those are recommendations, if they try to force or scare you that bad things will happen to your car if you don't do it.. I recommend looking for another dealership or shop somewhere.

BTW: if you're using k&n oil based filters it might clogged up your MAF.

Re: Mass Air Flow Sensor & Throttle Body Service
 

1. does have throttle body. it's neatly, and quite inaccessibly, tucked between the engine and firewall, down on the far end of the air intake hose. can't even take a good pic of it, but it's the shiny metal piece down there:
http://i302.photobucket.com/albums/n...z/100_0651.jpg

2. here's your MAF, mass air flow sensor:

http://i302.photobucket.com/albums/n...z/100_0649.jpg

it is very easy to remove, simply undo 2 screws holding it in place, unhook harness, and take it out.
It has a small ampule looking thing hidden deep inside a plastic tube, some sort of a sensor, and that has tendency to get covered with crud. as those work off resistance measured between sensor and electrode, any crud build up slowly de-activates full function.

it is very easy to clean. use MAF sensor cleaner, and make sure you do get it onto that ampule hidden inside, or you did not clean it at all. been there. MAF will throw a CEL and a specific error code.

Re: Mass Air Flow Sensor & Throttle Body Service
 

oh, and MAF has 2 O-rings sealing it in place. when they go bad, air starts leaking past them, and skews the function. few cents fix either.
reason I know all this is my wife's RX300 has exctly same one, and I was through all this few times already.

your best bet to keep it all nice and clean is to use petrol with cleaning additives only. Chevron, Texaco Shell, Exxon.... Or run cleaners through petrol on regular basis.

Re: Mass Air Flow Sensor & Throttle Body Service
 

Is there a way to check for a "sticky" throttle plate without doing any disassembly on the 2007 TCH? Thanks in advance.

Re: Mass Air Flow Sensor & Throttle Body Service
 

If you have a video inspection camera with a long fiber optic lead, you should be able to observe it from the air cleaner box. By long lead, I'm talking about something like this:

http://buy1.snapon.com/catalog/item....re&dir=catalog

If not, by the time you get down to it, you might as well clean it.

By the way, my 2008 has over 130,000 miles and has never had the throttle body cleaned. As long as you change air filters often and use a good grade of gas, they should be fine for at least 100,000 miles.