P0505 code - 2001 Nissan Maxima

That code is for the idle speed control valve. Please follow the link P0505 Honda Idle Air Control Valve

P0505 should be the IAC (Idle Air Control) System Malfunction

Hope this helps

P0505 14 ICS Malfunction
http://www.ericthecarguy.com/29-obd-codes/obd-ii-codes/honda-obd-ii-specific-codes/215-p0505-idle-air-control-valve-malfunction-honda

p0120 means you have a throtle position sensor problem could get expesive if throtle body is bad p0505 is same problem it means throtle idle controle valve problem hmm short bad ecm or bad throtle body hope this helps

P0505 - Idle Control System Malfunctionhttp://engine-codes.com/p0505.htmlForum CodePossible causes- IACV-AAC valve harness is open or shorted
- IACV-AAC valve poor electrical connection
- Faulty IACV-AAC valve

Read more: http://engine-codes.com/p0505.html#ixzz1zVJIt34L

P0505: Idle Air Control Valve System fault, Code P0505
-Vacuum leak
-Dirty throttle body
-IAC motor defective
-Poor electrical connection to the IAC valve, hope this helps and good-day !

Its the IAC idle air contorll unit its on the air horn and controlls the air flow at idle This code is saying that something is malfunctioning it is not saying at what RPM it is happening at there is 5 or 6 differant codes for this and they run from P0505 thought P0509 but if you are geting P0505 i would just replace the unit but check the connection to it first it may be a bad connection it dose get weather and heat and that cerates problems with contacts

P0505
Idle speed continues to vary greatly from the target speed
(2 trip detection logic)
IAC valve is stuck or closed
Open or short in IAC valve circuit
Open or short in A/C signal circuit
Air intake (hose loose)
MARKO

this code make reference to low idle engine,maybe the throttle body is dirty , air filter clogged, vacumm leak , pcv valve clogged, check for thoses

p0505 is a code for your IAC (idle air control valve) located right below the TPS (throttle positioning sensor). Beware it is not necessarily the sensor. If you use a test light on the connection coming to it while the vehicle is running and rev the motor each terminal (probably four) should flash. In this case it is most likely your sensor. If not it is in the wiring or your pcm.