Valve clearances do need adjustment, just that it is not required too often.
Here are the diagnostics for P0505, see if you are interested in going through them.
DTC P0505: IDLE CONTROL SYSTEM MALFUNCTION
NOTE: If DTC P1508 is set with DTC P0505, trouble shoot DTC P1508 first, then recheck for DTC P0505.
1. Start engine. Hold engine speed at 3000 RPM under no load condition with transaxle in Neutral or Park until radiator fan comes on. Allow engine to idle. Using scan tool, ensure throttle position is about 10 percent with throttle fully closed and engine coolant temperature at 194-205 F (90-96 C). If throttle position and/or engine coolant temperature are as specified, go to next step. If throttle position and/or engine coolant temperature are not as specified, repair faulty sensor circuit.
2. Check engine speed with no load (headlights, blower motor, rear defogger, radiator cooling fan and A/C off). If engine speed is 680-780 RPM, problem is intermittent. System is okay at this time. If engine speed is 680 RPM or less, go to next step. If engine speed is not 680 RPM or less, go to step 4.
3. Disconnect Idle Air Control (IAC) valve 2-pin connector. If engine speed does not decrease or engine does not stall, replace IAC valve. If engine speed decreases or engine stalls, adjust base idle speed. If base idle speed cannot be adjusted to specification, clean throttle body ports.
4. Turn ignition off. Remove air intake duct from throttle body. Start engine and allow it to idle. If vehicle is equipped with a manual transmission, go to next step. If vehicle is equipped with an automatic transmission, place a finger on lower port in throttle body. If engine speed does not decrease, go to next step. If engine speed decreases, check engine coolant level and for air in cooling system.
If cooling system is okay, replace fast idle thermo valve.
5. With engine at idle, place a finger on upper port in throttle body. If engine speed does not decrease, check for vacuum leaks and ensure throttle valve is completely closed. Repair as necessary. If idle speed decreases, adjust base idle speed to specification. If idle Speed will not adjust to specification, replace IAC valve.
Wednesday, August 10th, 2011 AT 10:10 PM