2003 EX almost 100,000 miles, showing code P0507 at Autozone - Idle control system higher than expected - probable cause - large vacuum leak - Throttle body concern - Faulty IAC vacuum.
Warning light appeared accompanied by a brief engine hesitation while warming up idling on cold morning. Ran normally the rest of the day.
Disconnected the battery to clear the computer, same thing happened again this morning while engine was warming up.
Any diagrams available to show which hoses to check first, or where exactly the throttle body and IAC valve are? Or do I need to buy a Haynes manual?
Please advise, thanks.

This issue just appeared after getting the vehicle back from the shop for a timing chain and tensioner replacement. Could there be a connection here? I read where the idle on Accords are sensitive to coolant change, which I imagine was replaced during repair.

 

A smoke test to look for vacuum leaks may be necessary to locate a possible leak.

Yes, it's possible that something was not reconnected during work on car or accidentally damaged.

A dirty IACV (sticking open when cold) could also cause this code. Perhaps cleaning IACV might help.

Diagnostic chart indicates to first look for vacuum leaks, then replace IACV if no leaks found. This may indicate IACV is not suited for cleaning or maybe?

good luck

 

So many times it seems the diagnostic charts don't say anything about cleaning parts, just replacing them. Nevertheless, if you don't find vacuum leaks just take off the IACV and look at it. Honda IACVs traditionally seem to be clean-able.