On some models a faulty Idle Air Control (IAC) valve can cause an engine surge at idle and set a Check Engine Light (MIL). Replacing the faulty IAC valve will commonly correct this problem.Google+
Car Problem Reports
Honda Pilot Check Engine Light on Due to Faulty Idle Air Control Valve
Honda Pilot Problem
Average Mileage: 131,000 mi (72,000 mi - 180,000 mi)
Visitor, 2003 Honda Pilot, 141,000 mi
Started with engine surging at idle. Then, while in driving in lower gear, the engine stays at higher rpms and does not shift smoothly (jumpy). After a period, engine light came on and VTM light also. More breaking power needed to slow vehicle and some bucking was noted.
Visitor, 2003 Honda Pilot, 180,000 mi
Also had a high idle and hard shift from park to drive or reverse. Replaced the IAC. Fairly easy to do.
check engine light went on. previous earlier experienced idling problems.