P056C Packard Custom is triggered when the bank 1 camshaft position sensor doesn't match the signal from the crankshaft position sensor. Other serious codes may cause this code to pop up, and they may come with dangerous drivability issues that may expose you to safety risks and cause damage to the engine in the long run.
Possible Causes :
Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.
Diagnostic trouble code P056C Packard Custom is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P056C Packard Custom.
Fortunately, P056C Packard Custom is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.