ECU 0505 code?

i've read several sites that say the 0505 code my car is throwing up is an "all good" code...my question is, if everything is fine with the car, why would it turn the "check engine light" on to tell me this? i had my car checked out and the mechanic said it was throwing a o2 sensor code, which we fixed...a few days after, it throws the 0505...i have a 97 gxe with 123K miles...any feedback would help me feel better about my car...thanks

Try reseting the ECU to clear all the codes stored in memory. I wouldn't worry about the 0505 code coming on. It's better to have the ECU tell you visually that everything's fine then for you to guess.

There was a huge debate about this over at maxima.org...no one knows why the ECU throws the 0505 code and turns the CEL on.

~THT

First off you are confusing codes 55 and P0505. 55 is no codes stored.Everything fine. Code P0505 indicates a problem with either the idle air control valve {IACV}or the auxillery air valve{AAC}.There is a diagnostic procedure to determine which system is at fault.You need a manual.

Also a side note.Since OBD2 {1996} no vehicle manufacturer has a "no problem found" code.Code 55 was for no problem found {nissan} pre '96.

Not according to my Haynes manual. When it flashes 0505, that's an all clear.

~THT

No disrespect intended.I'm going by factory shop manual.And 14 years Nissan tech. experience.{Don't use Haynes manuals as they rarely say much}If were talking DTC P0505 .{don't know what an 0505 code is} it is not an all ok code.Factory manual clearly states so.How are you extracting this 0505 code{andywang3}

None taken. What I meant by flashing 0505 is when you put the ECU/PCM in diagnostic mode and it blinks five times quickly then five times slowly. On the other hand, P0505 is an IACV problem as you said and is a result of two short blinks and five long ones.

~THT

i got the 0505 code from the diagnostics mode...the "check engine light" blinked 5 long and 5 short...thanks alot for everyone's help on this.

Ok. The 0505 code is a ECM code{not DTC like I thought,sorry about the confusion}It is a "no problem found} code.Make sure you are returning the mode selector{ecm screw} to fully counterclockwise position.This will take the ECM out of diagnostic mode.If trouble persists let me know and I will find the answer.

thanks alot! anyways, i turned the screw counterclockwise and it turned the light off...BUT, after a couple days, it popped up again...i'm assuming it is gonna throw another 0505 code, but i haven't tried yet...is there anyway to turn the check engine light off? or, am i just destined to have the light on forever...seriously, thanks for the help!