Fault Code P0300 H C

by Ron

2003 Corvette. Was idling rough, but ran fine under throttle.

Water splashed underneath engine bay, began to show engine light, first flashing then steady.

Engine began to run very rough, did not accelerate nearly as well.

Checked the DIC and the only current fault code is under the 10 PCM. P0300 H C.

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Oct 16, 2016
rough idle NEW
by: Anonymous

Changed out spark cables. Problem went away.

Oct 15, 2016
Engine misfire after getting wet NEW
by: Louis Nagy

This is a common problem on a c5 with cold air intake ,water reaches the mass air flow sensor and you can ether pull it apart and clean it or wait for it to dry,,(I would inspect and clean) brake Kleen works great, and make sure you have a front hood gasket installed .GM did not put one there so it is something that will have to be done when a cold air intake system is installed,🍻 Cheers

Jan 17, 2016
by: Chris

This code says your car is miss-firing. We are going to guess its related to water being ingested into the engine or intake track. Under idle conditions you will have more vacuum pulling any standing water into the engine. We would recommend not driving the car until this can dry out naturally over time. You should be ok but stay away from puddles many Corvette owners have changed engines for hydrolocking in big puddles. Consider your self lucky! If you want to read codes easier with your Corvette or any car try this C5 Corvette ScanTool 425801 OBDLink SX USB: OBD Adapter/Diagnostic Scanner
You can read all engine parameters in real time. Its pretty cool just to watch even when nothing is wrong!

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