P0492 refers to one of the two secondary AIR Pump systems. The "H C" suffix means that it is both a historical as wel as current condition. This is an emissions item, and the pump only runs for a short time at cold startup. It is probably something you'll want to take care of, but it won't harm the car to drive it with this code.
There are two air selonoids and shut-off valves which frequently become "frozen" or rusted shut. One is located by the rear of the intake manifold and the other is on the driver side above the exhaust manifold...with a hose going to the air cleaner. Look for any obviously broken or disconnected hoses or connectors. If none found, you might get lucky by disconnecting the hose upstream of the valve and spraying it liberally with penatrating oil or WD40.
The code MIGHT be a AIR (smog) check valve but many times it is not
AIR is injected into exhaust on COLD starts for about 2 minutes
IF there is a problem with FRONT 02s the error would trigger but ALSO is the rear 02s have a problem would also trip the same AIR DTCs.
Use a OBD scanner on cold start, if the front 02s are not within coldstart range it may then be the fronts
If the short term fuel trims are not correct during cold start running then the REAR 02 are at fault OR
1. Exhaust leak
2. clogged CATs.
3. excess exhaust backpressure.
4. water vapor into the AIR pump
02 sensors degrade over time and for best AFR and functional fronts should be replaced about every 30,000 miles