After that, the current is reduced to the amount needed to hold the injector open. The code P0204 stands for Injector 4 - Circuit Malfunction. This means that the PCM had detected a malfunction in the fourth injector circuit. In other words, the PCM commanded the injector on/off but did not see the subsequent change in electrical current. P0203 Citroen Description. Engine Control Module (ECM) checks the injectors circuit resistance and monitors the voltage drop during normal operation. The ECM will trigger the P0203 Citroen code when the resistance or voltage drop at the injector 3 is out of specifications. Citroen Vehicle: 2013 Citroen,2012 Citroen,2011 Citroen,2010 Citroen.