Hi all,

I have a 2001 RX300 AWD. It has around 63,000 miles on it. I had the timing belt, spark plugs and the 2 fuel/air sensor replaced around 62,000 miles in August 2009.

About 2 weeks after the timing belt, etc was done, I had a hard time starting it. It would take sometimes 5 twists of the key for the RX to start. I thought it was related to the timing belt, etc. work, but I did some searching on CL to see if anyone else had the same problems I had.

After searching, I came across the DIY IACV cleaning. I cleaned out the IACV myself and it started fine after that (started on the first twist of the key). I noticed then that the RX was idling at high rpms at idle or coming to a stop (sometimes around 1,200 or 1,300 rpms)...even after being warmed up and driven for a while. I cleaned the IACV a second time, and the idle calmed down a little and idled around 1,000 rpms.

Now about 2 weeks after the 2nd cleaning, the CEL and VSC light came on today. I scanned the RX with the OBD2 scanner and the code states P0505 (Idle Control System Malfunction).

Should I try another IACV cleaning? Or do I need to replace the IACV itself? Anyone have a the actual part number for the IACV? Will I damage the RX in any way if I continue driving it with this Idle Control System Malfunction?

Thanks in advance for your help.

 

I swear when I get my hands on my new OBD2 scanner (almost at a decision whether to go laptop based or a handheld version), I'll be able to toy with some of these codes. I'll still can't get myself to decide.

Anyways, on the P0505 you've got two possibilities. One, it's the IACV. Two, it's the air hoses. With regard to two, that means anything that can be allowing extra air into the intake. I'd check every last hose around the air box and IACV for anything.

You won't damage anything, but I would be curious to know what your RPMs are in Park and in Drive when you are in Idle.

I had a P0505 if I recall last December and in that case the issue was that the IACV was stuck in the open position and I had to really get in there and clean it good and make sure nothing was sticking.

 

I have the CEL and VSC light on as well. They come on about once a month, then go off after a day or two. No difference in idle or driveability before or after the light activations. I'm sure I should take it in and have it checked, but after reading so many different solution on CL to fix it ( gas cap, 2,000,000 different sensors to clean/replace) I will just let it go until they remain on for extended period or the performance/driveability of the RX worsens.

The more I read this forum, the more concerned I am about the vehicles we have bought. Seems like a ridiculous amount of sensors in every area imaginable, ALL are extremely costly to replace (dealer work) and many when replaced, do not solve the problems. Add to that the transmission failures, timing belt etc. and it does not give me much confidence in the longevity of our RX's. Only time will tell I guess.

Good luck with your issues, I hope you can get them sorted out without draining your entire retirement savings.

 

Hi LexMex,

Thank-you for your suggestions. I am also tempted to buy another more detailed OBD2 scanner like what you are thinking about. I have the same OBD2 scanner that you have (the one you posted a picture of a while back).

On my 2nd IACV cleaning, I blasted that area with carb cleaner like crazy. I must have used up half of the can. I re-connected all the hoses and re-checked the connections 3 times to make sure it was all good. I thought that the reasons why I had the high rpm's after my first cleaning was cuz I had an air leak somewhere. Maybe I did cuz after the 2nd cleaning, the rpm's were only around 1,000 or so at idle and when stopped. Who knows? Maybe I screwed up the connections again! I will re-check the connections tonight when I get home. When I get back home and drive the RX, I will give you an update as to the rpm's in Park and at idle and when at a stop light.

With the holidays coming up, I have some time on my hands, I am debating with myself whether or not to just replace the IACV valve and be done with it. I found the Lexus/Toyota part numbers online. They are:

22270-20050 (IACV itself)
22215-20010 (IACV gasket)

Maybe by just replacing the IACV itself, I can once and for all get rid of the P0505 code. The RX is primarily my wife's vehicle. It is sitting in the garage at home until I found out that it was still safe to drive with the P0505 code present.

Thanks again for the suggestions, LexMex. I will update ya later.


Hi ByTor,

I understand your fustrations with all the CEL and VSC lights appearing on your dash. Our RX's are getting older, and as they age, they will require more maintenance (just like us humans I guess!). My RX is now over 8 years old and it has served me well these past 8 years. My wife still loves to drive it.

I try my best to try and repair it myself (if I can handle it). If I do not possess the skills to DIY, then I have an independent mechanic who I can take my RX to. I try and avoid the Lexus dealership as they are very expensive. If my independent mechanic cannot handle it, then my last resort is the Lexus dealership. My indie is cheaper than the dealership and I trust him to not overcharge me or do any unnecessary work.

Best of luck also with your RX issues, ByTor. I hope you can find some solace here on CL by getting great advice for ideas on how to resolve your issues.

 

Hi LexMex,

I came home and checked the hoses and they all seem to be on there correctly. I then started up the RX. It idles at 1,000 rpm's on a cold start. I put it in Reverse, and the idle stayed at 1,000 rpm's. I put it in Drive and it still had rpm's around 1,000 with my foot on the brake. I drove it around town for about 20-30 minutes and travelled about 15 miles or so. The coolant temp guage was at its normal spot (pegged at half between cold and hot). When I came to a stoplight, the idle was about 1,000 rpm's.

Just for fun, I shifted to Neutral at a stoplight and the rpm's jumped to 1,500 or so. When I put it back in Drive, the rpm's drop back down to 1,000. When I also put it in Reverse (shifting from Neutral or Park), the rpm's drop to 1,000. When I came home and parked it in the garage and put it into Park, the rpm's also jumped to 1,500 or so.

Driving it around town, the idle never strayed too far from 1,000 rpm's when coming to a stop. But once I got it into normal operating temperatures, when I shifted it into Neutral or Park, the rpm's jumped to 1,500 rpm's.

Maybe my IACV is really screwed up. I will probably order a new one and see if this makes the RX happy. I will probably install it over Thanksgiving (if I get the parts in time). I don't know what's wrong with the RX. Hopefully, a new IACV will help with the idle issues and the P0505.

 

Only things I try when I get that are disconnecting the battery cables and then usually I will go after the IACV next. I know the little flap in the IACV can go bad after a while and necessitating replacement (don't think they sell it separately).

BTW, I came to a final decision on a scanner, and it looks like it is going to be this, http://www.obd2allinone.com/

Haven't ordered it yet, but with my birthday coming up, that's what I am going to get and hopefully once I have it will be able to show screen shots of what is occurring when I get certain types of errors.

 

Hi LexMex,

Happy early B-Day! That looks like a great scanner. Once you buy you new toy, please let us know how you like it!

I broke down and ordered a new IACV yesterday. I probably won't get the part until after Thanksgiving. So I will probably install it sometime after Thanksgiving.

Thanks again for the advice. I will post up again after I install the new IACV to see if it makes a difference to the idle and if I get any more CEL's.

 

One of my neighbors has 2 Acura TLs, not the previous one, but the one before that, and he and I were talking about how useful that scanner would be once we get it up and running on my laptop since he's got some issues with those cars we'd like to tackle, too. I personally wish I had my head on straight and had one of these in Mexico. I am going to delay a bit, because I want to if I can get any black friday deal on it, though I may hop on it earlier, but the fact it can use so many different types of software, especially digimoto, makes it appealing. Moreover, if some new software comes along, this device I am sure will work since it will cover the CAN protocol.

Keep me updated with the IACV.

 

I tried changing out the IACV myself...but I could not get any of those screws to budge on the throttle body. After trying for almost an hour, I gave up. I called up my independent mechanic and he had room for me today to help me rip out and replace the IACV.

I am happy to report that the RX idles back at 700 rpm's or so (or whatever the rpm's are at the second hash mark above the "0" on the tachometer). Before replacing the IACV, it was idling around 1,000 rpm's or so. Also now, when I shift the transmission into Park or Neutral, the rpms stay at 700. Before replacing the IACV, the rpm's would jump up to 1,500 or so when I shifted it into Park or Neutral.

No CEL light on the dash so far. I have driven it for about 50 miles so far. Seems like the engine is much happier with the new IACV installed.

Looks like cleaning the IACV twice did not work for me. It was a good exercise to isolate what was causing the RX to not start upon the first twist of the key (the original reason I cleaned the IACV). After my first cleaning of the IACV, the RX started fine. What caused me to replace the IACV altogether was the P0505 code.

I will report back if any CEL lights up.

Thanks again Lexmex for your help.