I am at a loss. While I drive my 2008 xl1200c, and Iet go of the throttle, the bike still is revving at the idle speed that I was travelling until I come to a complete stop. So If I am doing 70, and I let go of my throttle and coast, the revs stay high. So it seems that the idle is trying to stay at the speed of what the bike is at until it comes to a stop. Sometimes, during this time, the engine light comes at time and I get the code, P0505-loss of idle speed control. The bike idles perfect and the only issue is the high revving until I stop.

I have done the following so far:

• Changed my air and fuel intake gaskets
• Checked for voltage drop from battery
• Oil in the crankcase is at just over half on the dipstick, so not too much
• Changed my IAC valve.

After all this, I brought the bike into the my HD dealer and they check ed it over for a few things and couldn't find the problem, they basiaclly check it for the exact same thing as I did. And stated that if I wanted them to go further, it was going to cost a bundle of money.

Has anyone ever encountered this issue and how did you solve it?

Thank you in advance for any response.


Here is what the manual says about this code(cut and pasted from another post on this site):

P0505 Loss of Idle Sped Control EFI
Summarized from 07 Sporty Electrical Diagnostic Manual:

P0505 - Loss of idle speed control

Loss of idle speed control will result if the idle RPM is +-200 from present idle speed and IAC motor is at zero or maximum for greater than 5 seconds.

- Loss of idle speed control doesn't necessarily mean that the IAC is bad. There are other causes such as intake leaks, misfiring cylinder.

- Leaking injectors can cause poor idle. To check for leaky injectors remove A/C. Then with throttle wide open, turn key to ON for 2 seconds and then off for 2 seconds five consecutive times. Replace injectors if there is any evidence of raw fuel in the bores.

- Vacuum leaks - check for leaks

- Contaminated fuel

- Excessive Oil in crankcase

- TP sensor reading greater than 1 % (cable misadjusted), battery less then 9 Volts, or vehicle speed sensor (VSS) greater than 0 will disable idle speed control.

- Loss of battery power to terminal 31 of ECM.

The speedometer signal is an extremely important input for the Delphi fuel
injection system. The ECM monitors throttle position and speed signal inputs in
order to properly maintain the set idle speed. If the ECM loses the speed signal
for any reason while the throttle is closed, the ECM assumes the vehicle is
stopped and will adjust the idle air control counts to bring engine rpm to the set
idle speed. This could set a P0505 code and adversely affect engine idle.

 

Some other good things to check here: https://www.hdforums.com/forum/sport...hway-ride.html