P0068 Citroen Eco is triggered when the bank 1 camshaft position sensor doesn't match the signal from the crankshaft position sensor. As you drive and when specific conditions are slowly met, the vapors will gradually purge from the charcoal canister and will get burned within your engine.
Possible Causes :
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. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.
Diagnostic trouble code P0068 Citroen Eco 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 P0068 Citroen Eco.
Fortunately, P0068 Citroen Eco is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.