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Throttle Body Replacement for Weird Idle Pattern?

4K views 12 replies 5 participants last post by  rpsedy 
#1 ·
Hello everyone,

Here are my symptoms:

My 2005 Automatic RAV4, when downshifting (such as coming to a stop light), will intermittently pop up the idle a few hundred RPMs. This sometimes causes a slight bump in the transmission. This is most evident once the vehicle is fully warmed up and doesn't seem to be a problem while it is still cold. I have talked with an independent Toytota mechanic and he suggested the Throttle Body should be changed, but will only do the job with a Toyota part which is one thousand US dollars. No thank you.

I brought the RAV to a dealer and they were unable to find anything wrong (doesn't inspire much confidence) after I provided a detailed description. There are no codes and I have already cleaned the throttle body and mass airflow sensor. I have 70k miles on this RAV. It seems like the engine doesn't behave properly as the vehicle is slowing down and tries to compensate excessively when the shift occurs.

Here are my questions:

1) Has anyone changed a throttle body to correct an intermittent condition as I have described above? Most of the descriptions I can find seem to suggest replacement only when there is a complete failure of the part. I am still able to drive the vehicle at this time, but don't want any transmission wear from this condition.

2) I am thinking of simply buying this part on Amazon, where the manufacturer claims this is an OEM part and identical to Toyota's:

http://www.amazon.com/C151-220300H0...xANcf6L&dpSrc=sims&preST=_AC_UL160_SR160,160_

Has anyone done a repair like this?

I think I will take a shot at the repair myself, but just wanted to take a last stab at getting some data before I take the plunge.

Thanks in advance!
https://masterscollege-my.sharepoin...tial\)|BA1CC9B0-7438-4C02-A6AB-5244AC7E640A/)
 
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#4 ·
IMO, you are wasting time and money on the TB, although it certainly can't hurt to clean it
the mechanic who suggested this was guessing, or worse, trying to fleece you
you didn't say whether this is something that just started happening or if it has always acted like this
if it has always acted like this, have you had the ECU reflashed?
I have a manual 2003, the thing has never idled properly, which is endemic of this version of the RAV4, although I have lived with it because it isn't the serious problem it can be with an automatic
if it just started, 2005 is a ten year old vehicle, is there a leak in a hose?
start with the simple and cheap
mechanics always want you to spend money because it goes in their pocket
 
#5 ·
MNRAV4,

Thanks for your reply. My RAV4 is in great condition with only 70k miles. I have not been able to find any leaks of any type.

When I first bought the vehicle in August, the idle was going way low to 400-500 rpms. After I performed an initial TB cleaning, it improved significantly, but the idle still pops up a few hundred with downshifting from 2nd to 1st. Because this behavior seems so closely tied to the operation of the TB, I cleaned it again, extremely thoroughly. I also cleaned the MAF sensor. Even with all this, the idle issue is still there.

I talked to what I believe is a very honest and reliable independent toyota mechanic and he suggested, based on what I had described verbally, that the TB replacement would likely remediate the problem. I took it to a dealer for a second opinion and they were not able to even find anything (although I don't think they followed my specific instructions since the issue occurs almost exclusively when the engine is fully warmed up).

I will check into the ECU flashing. Please let me know if you have any other thoughts.
 
#6 ·
MNRAV4,



When I first bought the vehicle in August, the idle was going way low to 400-500 rpms. After I performed an initial TB cleaning, it improved significantly, but the idle still pops up a few hundred with downshifting from 2nd to 1st.
so do you consider the idle to now be fairly normal except when downshifting?
when downshifting from 2 to one, is that the only time the idle is affected?
the first car I owned was a 1971 Celica with manual transmission, every car since has had a manual transmission, I have owned my RAV4 since new and the idle while shifting gears has always gone up a couple hundred RPM, I have never liked it but it wasn't until I owned it about 10 years that I learned about the ECU needing reflashing because the original wasn't correct. By that time I was used to it, so I have never bothered, that and the fact to have a dealer do it would cost me bucks and it is only an annoyance that I have gotten used to car gets great mileage and otherwise is a great vehicle.
There are a number of things that could cause the idle to vary/move around, but none I can think of that only affects a downshift from 2nd to first, I am assuming yours is manual also. Of course engine rpm should go up after a downshift, my assumption is that you mean the idle goes up during the shift, as I said, mine does that for every gear shift, is most noticable on an upshift, and more noticeable (annoying) in lower gears.

I recommend continuing to post here, someone may see it who has had a similar problem.
 
#7 ·
Thanks for your reply MNRAV4,

The idle is pretty good overall except when downshifting. The interesting thing is that it is far smoother in operation when the vehicle has not fully warmed up yet. This is what makes me suspect the throttle body, since I believe it has some responsibility in negotiating idle RPM at different engine temps. This RAV4 is actually an automatic transmission, not a manual.

I still haven't purchased a throttle body to do the replacement yet... I am still toying with the idea of consulting with one more service guy to see what they think. However, at the end of the day, I am confident that what it is doing is not normal.

BTW on the issue of reflashing the ECU, what year RAV4 are you talking about? All the references that I have found seem to refer to RAV4's older than mine. Mine is a 2005.

I will definitely post what I find as I move forward. Hopefully someone else can benefit.
 
#8 ·
Hi rpsedy - I am experiencing the exact same symptoms on my 2005 RAV4 (over 122k miles). My idle also fluctuated down to as low as 500rpm when the a/c kicked in, so I did the TB and MAF cleaning which worked great. On a cold engine, my RAV's shifting seems fine until the engine warms we see the rpm surges when coming to a stop. Did you ever discover a remedy to your vehicle's rpm surge problem?
 
#9 ·
Hey Shaka, thanks for your post. I finally ended up taking my RAV4 to a highly reputed Toyota mechanic (the second one I have dealt with outside of the dealer) for a final stab at an opinion on what was happening with the vehicle. I ended up driving it around with him for quite a while and the symptoms did appear, but only sporadically. In a nutshell, he didn't seem to think the behavior was outside the realms of normal. At the end of the day, my best guess on the cause is the throttle body itself. I have researched countless forums, looked at the service manuals, got three different opinions and none of it seems to have definitively identified the issue.

Based on my understanding of the functions of the throttle body, I believe that replacement is the best shot at remediating the problem. If a sensor or contributing system were at fault, I would think that we would most likely see an engine code of some type. I have nothing.

The biggest problem with replacing the throttle body is the Toyota part cost is $995. I am unwilling to pay that much for a TB.

I have two Amazon options:

Aftermarket:

http://www.amazon.com/220300H041-To...1oHHodL&dpSrc=sims&preST=_AC_UL160_SR160,160_

OEM Replacement (claims to be identical to the Toyota part)

Amazon.com: C151 220300H021 04-07 Toyota Throttle Body RAV4 Highlander Solara Camry Scion tc 04 05 06 07: Automotive

The only problem I have now is that the photo of the product is missing a pipe that my throttle body has. In other words, they don't match in appearance. At this point, I just ran out of steam on pursuing the resolution. It is definitely driveable, and my wife doesn't even notice the issue when she drives it, but it personally drives me nuts and I am convinced (in spite of the difference of opinion with the mechanics) that something is still wrong. If I can muster up the energy, I will figure out which amazon option works and then replace it myself and report the results. I wish I had more to say at this point. I hope this helps.
 
#12 ·
Hey Shaka, thanks for your post. I finally ended up taking my RAV4 to a highly reputed Toyota mechanic (the second one I have dealt with outside of the dealer) for a final stab at an opinion on what was happening with the vehicle. I ended up driving it around with him for quite a while and the symptoms did appear, but only sporadically. In a nutshell, he didn't seem to think the behavior was outside the realms of normal. At the end of the day, my best guess on the cause is the throttle body itself. I have researched countless forums, looked at the service manuals, got three different opinions and none of it seems to have definitively identified the issue.

Based on my understanding of the functions of the throttle body, I believe that replacement is the best shot at remediating the problem. If a sensor or contributing system were at fault, I would think that we would most likely see an engine code of some type. I have nothing.

The biggest problem with replacing the throttle body is the Toyota part cost is $995. I am unwilling to pay that much for a TB.

I have two Amazon options:

Aftermarket:

Amazon.com: C151A 220300H041 04-07 Toyota Scion Throttle Body Camry Highlander Solara RAV4 Tc 04 05 06 07: Automotive

OEM Replacement (claims to be identical to the Toyota part)

Amazon.com: C151 220300H021 04-07 Toyota Throttle Body RAV4 Highlander Solara Camry Scion tc 04 05 06 07: Automotive

The only problem I have now is that the photo of the product is missing a pipe that my throttle body has. In other words, they don't match in appearance. At this point, I just ran out of steam on pursuing the resolution. It is definitely driveable, and my wife doesn't even notice the issue when she drives it, but it personally drives me nuts and I am convinced (in spite of the difference of opinion with the mechanics) that something is still wrong. If I can muster up the energy, I will figure out which amazon option works and then replace it myself and report the results. I wish I had more to say at this point. I hope this helps.
The newer TBs don't have that pipe. Toyota has a TSB dated 4-19-2010 T-SB-0111-10 where they eliminated it. This is for 2004-2008 Rav4s.
 
#10 ·
Thanks for the quick response, RPSEDY. The surge symptoms were present prior to cleaning the TB and MAF. I removed the TB for a through cleaning and got the idling issue resolved but recently the idle problem reoccured so this time I just sprayed TB cleaner just a tad and it restored the idle again. My vehicle is not throwing any codes as well. After pulling the Throttle position PID values, it revealed the TB valve is within normal parameters (15-17%) at idle. I suspect a relearn process was needed, however, I found that was only necessary for new TB install.
 
#11 ·
Shaka, the only other diagnostic approach that I might take when I have a little more time is to purchase a less expensive Android tablet with a bluetooth sensor to see if I can get any other info from the computer, in real time, while the problem is occurring. See this post for more details:

http://www.rav4world.com/forums/87-...ng-dashboard-screen-computer-information.html

What are you going to do for a next action on your RAV?
 
#13 ·
Thanks viriginiajim,

I looked up the service bulletins for my RAV4 as a result of your post and saw the design change in the TB as well as a different TSB for 'techstream ECU Flash reprogramming'.

2005 Toyota RAV4 TSBs (Technical Service Bulletins) | ToyotaProblems.com

I called Toyota directly to talk to them about these TSBs to see if I could figure out why both of those TSBs were necessary and was not able to get much of any information. The best they could suggest was that I go to another dealer and specifically reference them to see if they could accurately diagnose the RAV4.
 
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