General Question about Error Code Readers

This is sort of a noobie question...I had an engine problem yesterday that caused the engine to shut off randomly. I managed to start my car this morning and had a check engine light...after fiddling with the fuses/sensors the check engine light turned off...So whatever error existed seems to be gone.

My question is: can a code reader pick up a previous error that is not currently active in the car? (its a 01' Hyundai Sonata BTW)

The computer stores both current and history codes. You should be able to read the history code as long as you didnt disconnect the battery and clear the memory.

All OBDII cars (1996 or newer) store codes that can be retrieved by inexpensive code readers. The codes are stored for various lengths. Some codes are stored for upto 50 ignitions... Some shops like autozone scan your car for free I believe.

Thanks guys!

50 read outs is quite a bit....i took the car to the shop...they're working on it now. They got back to me saying that they got readout P0335; crankshaft sensor malfunction...which may be about right for random engine shut offs.