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Code P0505

Tiny
KORJES
  • MEMBER
  • 1998 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 207,000 MILES
I've replaced the IAC valve, thoroughly cleaned the throttle body and can't find any vacuum leaks. Idles very high and can't figure this out. Please help.
Thank you
Saturday, November 13th, 2021 AT 11:30 AM

6 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

I would try disconnecting and plugging the hose on the brake booster to see if it is causing the issue.

https://www.2carpros.com/articles/engine-idles-too-high

Use some spray such as brake Kleen and spray around the intake manifold and see if the idle changes.

https://www.2carpros.com/articles/throttle-actuator-service

I know you said you cleaned the throttle body really well but check and make sure the throttle plate closes completely. If it is open at any amount, it will raise the idle.

Roy
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Saturday, November 13th, 2021 AT 1:48 PM
Tiny
KORJES
  • MEMBER
  • 5 POSTS
It closes fully. I've cleaned all around the edges of the plate as well. I just now went and replaced the PCV valve. No change.
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Saturday, November 13th, 2021 AT 1:50 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, spray around the intake and check the booster as I suggested.

Roy
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Saturday, November 13th, 2021 AT 1:57 PM
Tiny
KORJES
  • MEMBER
  • 5 POSTS
Okay, so I got a new can of cleaner and sprayed all the way around this morning and didn't really hear any change in the idle. Understanding that part of what's happening is the idle fluctuating a bit on its own. I also pulled the vacuum line off the brake booster last night and plugged that up with no change.
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Sunday, November 14th, 2021 AT 4:31 PM
Tiny
KORJES
  • MEMBER
  • 5 POSTS
I wanted to mention this as well. When the car is in drive or reverse, it does not seem to fluctuate its idle and hangs out around a thousand whereas when it's in park is revving up to 2400 and then back down to say 14 1500.
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Sunday, November 14th, 2021 AT 5:19 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, you are going to need a scan tool to hook up to your car and monitor the IAC valve. The scan tool can command the valve to move in and out to verify that it is moving freely.

If that is working correctly, then good chance the ECM is a failure as it controls the operation of the motor.

Roy
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Monday, November 15th, 2021 AT 3:44 AM

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