P0505 - Idle Control System Malfunction Plus Vsp Light

[vevro]

Both engine check light and VSC off lights similtaniously went off. I looked up the code and there was a suggestion to replace the fuel filter; can someone please confirm if that really works. And why did the VSC light went off too? Please help.

[blake918]

I just checked my Lexus manual (it's for a '95, but it shouldn't be too too different from the '99.), and I didn't see anything about the fuel filter. They mentioned checking these "trouble areas:"

-IAC valve is stuck or closed

-Open or short in the IAC valve circuit

-A/C idle up VSV

-Air intake (hose loose)

I believe that VSC will be disabled any time the CEL comes on as a safety measure.

[vevro]

I just checked my Lexus manual (it's for a '95, but it shouldn't be too too different from the '99.), and I didn't see anything about the fuel filter. They mentioned checking these "trouble areas:"

-IAC valve is stuck or closed

-Open or short in the IAC valve circuit

-A/C idle up VSV

-Air intake (hose loose)

I believe that VSC will be disabled any time the CEL comes on as a safety measure.

Thanks for the suggestions Blake, I'll do the checks then i get home tonight.

I think my car has a mind of its own. After driving about 10 miles this morning both engine check and VSC lights flickered and disapeared. Very strange. Even before the lights went away i didn't feel any change in throttle response or drop/increase in RPM.

[oohryry]

Both engine check light and VSC off lights similtaniously went off. I looked up the code and there was a suggestion to replace the fuel filter; can someone please confirm if that really works. And why did the VSC light went off too? Please help.

Lexus says the VSC light goes off whenever the computer senses there is a problem. Did your rpms jump or the throttle change in any way. I hate this fail safe feature on my vehicle. I always have to cut off the engine and restart it to get control. Gets kind of dangerous if it goes off when you are pulling into traffic or while making a left hand turn with oncoming traffic approaching.

[vevro]

In case someone comes across this thread and needs an answer. I've managed to fix the problem by cleaning the throttle body and the fuel system. It took approximately 40 minutes for a kit to perform the necessary fuel-injector clearing.

This was definitely a long over due maintenance for my car with 140k miles.

[ezekielj007]

Vevro, yesterday I ran into the same issue you had. Can you or anyone else elaborate on the solution to fixing this issue? It would be a great help to me. BTW.