((Po505 code)) I have tried everything I know. Please some help.

4runnersforlife · May 14, 2025

Was this ever solved? I am having similar issues....

RumHamRunner73 · May 14, 2025

4runnersforlife said: ↑

Was this ever solved? I am having similar issues....
Click to expand...

Not 100% updated as OP hasn't been back for an update since October 2023

4runnersforlife · Jun 6, 2025

I finally solved my issue...40$ junkyard ECM and it runs like new again

Harold · Jun 22, 2025 at 8:15 PM

Devo in LA said: ↑

Hi Harold.
I have been having basically the identical problem for about 4 years now.
At first the car was having a problem starting cold until I hit the gas a little then it started up.
So I replaced the IAC valve with one from the internet, it is just a plug in thing, but as soon as I started the car it had a high idle (from 1100 to 1600, sometimes going to 2000) the P0505 was showing and wont go away for me either.

A couple years ago I had an experienced mechanic try to fix this. He replaced the IAC with 2 different new units and the code wouldn't go away. He checked and bypassed all of the sensors supposedly associated with the IAC system, smoke tested the engine for leaks and there weren't any, even replaced the ECU and the code is still there. The light and code have been on for awhile, and the engine idles around 1100 to 1600rpm, but the truck runs and drives fine. I took a chance and got a new IAC from a Toyota dealer for almost $400, put it in, and the code is still there and the idle is high. I have also tried several training methods for the idle and nothing. I need this truck to pass Cal smog, they won't check the car because of the high idle and the CEL being on, and this problem won't go away.

The truck is at another mechanic now and I'm waiting to see if they can fix it. So far they have found out that the center wire of the IAC plug is 14v when they say that it should be 7v or 8v. I will find out tomorrow if they have gotten anywhere.

I see that it has been a few years since this post but are you still having this problem?
If I cant fix this I'll need to get rid of the truck and I don't want to.

If you know anything could you let me know.

Thanks,
Hope your day is better than mine.
Click to expand...

hello there !!!!

guess what. I still ha e the 4runner of course. but I still dealing with the stupid code.

have you been able to fix yours ??

Harold · Jun 22, 2025 at 8:16 PM

RumHamRunner73 said: ↑

Not 100% updated as OP hasn't been back for an update since October 2023
Click to expand...

I still dealing with thus issue.

Harold · Jun 22, 2025 at 8:18 PM

4runnersforlife said: ↑

I finally solved my issue...40$ junkyard ECM and it runs like new again
Click to expand...

glad to hear that!!! how hard was to replace it ? I might have to do that at some point.

ToyotaGal · Jun 22, 2025 at 10:54 PM

Hello! I am curious .. how did you finally figure out it was the ECM? (had to ask my friend google what it is) I kept getting P0303 code before having no choice but to let my 4R sit because no one wanted to take on the work.

Harold · Jun 23, 2025 at 12:17 AM

ToyotaGal said: ↑

Hello! I am curious .. how did you finally figure out it was the ECM? (had to ask my friend google what it is) I kept getting P0303 code before having no choice but to let my 4R sit because no one wanted to take on the work.
Click to expand...

P0303 is just a Misfire in a cylinder.
this post is specifically about po505

4runnersforlife · Jun 23, 2025 at 5:12 AM

Harold[OP] said: ↑

glad to hear that!!! how hard was to replace it ? I might have to do that at some point.
Click to expand...

4runnersforlife · Jun 23, 2025 at 5:13 AM

It was pretty simple, it's behind the glove box

4runnersforlife · Jun 23, 2025 at 5:15 AM

ToyotaGal said: ↑

Hello! I am curious .. how did you finally figure out it was the ECM? (had to ask my friend google what it is) I kept getting P0303 code before having no choice but to let my 4R sit because no one wanted to take on the work.
Click to expand...

I replaced everything related to the codes, checked all wiring and grounds until there was nothing left and it had to be the ecu

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((Po505 code)) I have tried everything I know. Please some help.

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