Fix code P1506 – Idle Air Control System Over speed Error
If you get this P1506 – Idle Air Control System Over speed Error code on a Ford vehicle with the Duratec engine, don’t start with an idle air controller valve (IAC) replacement. This vehicle has a LOT of vacuum leaks and that can cause serious idle problems. Air leaks into the engine AFTER the MAF has already metered the incoming air. So the oxygen sensor sees a very lean exhaust. Since the vehicle is at idle, the computer tries to reduce incoming air by shutting down the IAC. Once it commands less air and stills sees an idle that’s too high, it sets a P1506 trouble code.
One of the common air leaks is in the rubber hose
going to the PCV valve. The hose has a 90 degree bend in it and it tends to crack there. So START your diagnosis by replacing both the PCV AND the hose. Many readers report that Ford doesn’t stop this hose. If you can’t find it, check the link below. Since this part has such a huge failure rate, Dorman has stepped into the market with a replacement. Install the elbow, clear the code and then see if it returns.
© 2012 Rick Muscoplat