P0505: idle control system malfunction?

[bassn_07]

Hey guys, This evening I got this CEL when pulling into my garage from a day of driving. I did a little research and it seems the culprit might be a loose vacuum hose. After popping the hood I didn't see any disconnected vacuum hose but I did notice a hose going to my airbox wasn't fully engaged. It was **** eyed a little but still on . Could this be the problem? It seems that the hose doesn't want to stay fully engaged and keeps cocking a bit. I'll pickup a hose clamp tomorrow to help secure the hose. What do you guys think, could this really be the problem? I have zero drive-ability issues and all seems well....?

To remove this ad, register today or login if you already are registered!

[jangy]

Could be that one. It should have a clamp on it but dunno what your setup is anymore. Reconnect it and add the clamp and see.

[bassn_07]

Originally Posted by jangy

Could be that one. It should have a clamp on it but dunno what your setup is anymore. Reconnect it and add the clamp and see.

I just replaced my 80mm TB and factory airbox with Renntech's 82mm and Renntech V3 airbox. I'm not sure how long it would take the CEL to come on but I disconnected while idling with no CEL. I wonder if it takes a while for it to come on?

I'll place a clamp on there and see if it helps. I didn't mention this before but I had the same CEL on my way home from LA. I reset the CEL and it just reappeared tonight? Hopefully I got it figured out and the clamp will permanently resolve the issue. We'll see.

[jangy]

It does take some time for the car to sense the vacuum or lack of.

In either case, as you said it has NOTHING to do with performance. Many people stick one of those small K&N filters on the end and that is enough. It is an emission thing and has nothing to do with the health of the ride. If it isn't that part, the "leak" can be tracked very easily. Don't bug. It was simple install. It should have had a clamp. When you do put it on, be careful of the CF. Just simple growing pains of doing so many mods so quickly. I would not bug on it.

[prodigymb]

weird i got that same CEL P0505. car is at the dealer now. they couldn't figure it out friday....

[bassn_07]

Originally Posted by prodigymb

weird i got that same CEL P0505. car is at the dealer now. they couldn't figure it out friday....

When you find something out let me know and I'll do the same. I'm going to start with the hose going to my airbox and start eliminating from there. After I go through all the lines I'll start questioning the TB.

[Ali_E55]

there is a house that comes out from the Y-pipe and goes under the right airbox to the top of the engine ( next to the S/C) maybe it got out or they forgot to put it after installing the new aribox

it may cuase this error

[jangy]

Oh yeah, Alan. Check not just the connection to the box, but the other end of the same hose. Mine came off once and it was under the box so I didn't notice it until a CEL.

[prodigymb]

my code was actually P0507 Idle Air Control System RPM Higher Than Expected

[bassn_07]

It seems that my P0505 code is okay now but now I get a P9026 "post catalytic fuel trim too lean" CEL. I got this same code with both the LET and PC tune..... I believe PC turned it off so I don't know why I'm getting CEL. All though I do hear a rattling sound inside my exhaust which makes me wonder if possibly my O2 sensor is broken. It's been like this since my mid-section exhaust install. Any thoughts on what else that rattling noise could be.

[prodigymb]

Originally Posted by bassn_07

It seems that my P0505 code is okay now but now I get a P9026 "post catalytic fuel trim too lean" CEL. I got this same code with both the LET and PC tune..... I believe PC turned it off so I don't know why I'm getting CEL. All though I do hear a rattling sound inside my exhaust which makes me wonder if possibly my O2 sensor is broken. It's been like this since my mid-section exhaust install. Any thoughts on what else that rattling noise could be.

do you have cats? or high flow cats? when cats break apart they rattle inside the exhaust.

[bassn_07]

Originally Posted by prodigymb

do you have cats? or high flow cats? when cats break apart they rattle inside the exhaust.

Yeah, I have 200 cell race cats. That could very well be the problem if that's true. Do you have the same problem?

[Zod]

Originally Posted by bassn_07

Yeah, I have 200 cell race cats. That could very well be the problem if that's true. Do you have the same problem?

are these the same cats provided with the LT's?
do you even have the LT's on ?

Thanks

[prodigymb]

Originally Posted by bassn_07

Yeah, I have 200 cell race cats. That could very well be the problem if that's true. Do you have the same problem?

I had oem cats, and after I got my EVO headers installed the oem cats blew through left side first and then the right side and made a noise in the exhaust for a week or so.

[jicl55]

...also have P505 code and can't figure out WTF is wrong... thinking vacuum leak also, but not positive, any help? WTF is wrong: P0106 and P0505 codes and rough idle

[MBH motorsports]

Originally Posted by bassn_07

It seems that my P0505 code is okay now but now I get a P9026 "post catalytic fuel trim too lean" CEL. I got this same code with both the LET and PC tune..... I believe PC turned it off so I don't know why I'm getting CEL. All though I do hear a rattling sound inside my exhaust which makes me wonder if possibly my O2 sensor is broken. It's been like this since my mid-section exhaust install. Any thoughts on what else that rattling noise could be.

What could be happening is you're getting unmetered air in. I had this problem and it turned out to be a air leak between the PipeLine that the Throttle body sits on and the supercharger. Some brake cleaner was sprayed in the area of suspect and the motor stalled, pin pointing the problem and the leak.

So it could be a loose fitting from the install allowing extra air in to the engine (my guess)

Or a few things. including above with also a bad cat or O2 sensor.

[bassn_07]

are these the same cats provided with the LT's?
do you even have the LT's on ?

No, these are the cats that Vadim provided with the mid-section exhaust system.

No, Chris is in the process of making my LT's.

...also have P505 code and can't figure out WTF is wrong... thinking vacuum leak also, but not positive, any help?

It seems that placing a clamp on the hose that connects to the airbox fixed the problem....we'll see. If that CEL comes on again I'll dig deeper and make sure all my vacuum lines are secure. GL and I hope you figure it out .

BTW...how does your car run with the CEL lit up?

What could be happening is you're getting unmetered air in. I had this problem and it turned out to be a air leak between the PipeLine that the Throttle body sits on and the supercharger. Some brake cleaner was sprayed in the area of suspect and the motor stalled, pin pointing the problem and the leak.

So it could be a loose fitting from the install allowing extra air in to the engine (my guess)

Or a few things. including above with also a bad cat or O2 sensor.

Thanks Mike. If the code comes up again I'll see if I could fix the problem.

One other thing I did notice, the connector on the airbox that the vacuum hoes goes on is loose. I noticed the fitting was loose as I was securing the clamp. I'll seal that up sometime this weekend.

[reent612]

Originally Posted by jicl55

...also have P505 code and can't figure out WTF is wrong... thinking vacuum leak also, but not positive, any help? WTF is wrong: P0106 and P0505 codes and rough idle

Yeah, I've had the P0505 for about a year now. Horrible rough idle, seems to have gotten worse. Replaced a couple vacuum hoses that looked to be dry rotting, but all other hoses seem to be new and secure. Also replaced the MAF sensor. Not sure what's going on. RPMs are too low to run A/C and come to a complete stop without it dying on me. Not so great for 115 degree AZ heat...

[Exotic-metal55]

I have the same code , after install of my 80mm tb. New motor and old motor. Tune made no difference weather the code came on or not. The code is random for me. May happen in 50 miles after a reset or 350 miles.

Checked all vacuum hoses and clamped them all too.

I feel some of these aftermarket TB`s are not calibrated for our cars. You put a larger TB on and it will let more air through at idle. Just a guess?

Going to put stock TB on and see if that fixes it for now.

[jicl55]

anyone been able to fix their codes yet?

[benz_addict]

bump
My car is going crazy with the idling problem after 15 mins of driving.
CEL came for throttle actuator position or something like that but I cleared it and hasn't came back since...

[Exotic-metal55]

Originally Posted by benz_addict

bump
My car is going crazy with the idling problem after 15 mins of driving.
CEL came for throttle actuator position or something like that but I cleared it and hasn't came back since...

What throttle body you have ? Stock? 80mm or 82mm?

[benz_addict]

Originally Posted by Exotic-metal55

What throttle body you have ? Stock? 80mm or 82mm?

Stock.
Also getting the code P0106 now... very rough idle after some time. I am going to replace the Manifold Air Pressure Sesnor ($53) and start from there. Good start?

[jikjak]

i get these 505 and 106 codes from time to time as well, seems like a common thing with people that have upgraded their TBs.

[chiromikey]

Originally Posted by benz_addict

Stock.
Also getting the code P0106 now... very rough idle after some time. I am going to replace the Manifold Air Pressure Sesnor ($53) and start from there. Good start?

parts wise it's cheap but I doubt you'll get it replaced for under 4hrs labor. iirc, you're gonna have to r/r at least the tb and maybe even the s/c.