I have a code for my 1995 Plymouth neon its p0505 with is a idle air control and i can not find any diagrams for what might be the problem could it be as simple as a new air filter??

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

Hope this helps

Error Code: P0505
Fault Location:
Idle Speed Control (ISC) System - Malfunction
Possible Cause:
-Wiring harness.
-Idle speed control (ISC) actuator/Idle air control valve (IAC) valve.
-Throttle valve tight/sticking.
-Engine control module (ECM).

have the vehicle scanned for check engine code most auto stores offer service for free

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 !

replace the idle air control

P0505 Idle Air Control System Malfunction That points to either an unplugged or bad Idle Air Control Valve (IACV).

there is no adjustment that can be made. You will have to have your iac motor checked it is attached to the side of the throttle body (idle air control).it is operated by the PCM. The PCM adjusts engine idle speed through the idle air control motor to compensate for load on the engine, or changes in coolant temperature or barometric pressure.

engine code PO505 is idle control system malfunction, check for vacuum leak

P0505 Idle speed control system malfunction.
Possible faults are:wiring,ISC actuator/IAC Valve, throttle motor,throttle valve tight/sticking, ECM

its the air intake throttle body housing find your air filter and follow its assembly back to the throttle body this what your looking for the throttle is stuck by some build up in throttle body use some fuel injector cleaner on and in the throttle body