The code P0203 stands for Injector 3 – Circuit Malfunction. This means that the PCM had detected a malfunction in the third injector circuit. In other words, the PCM commanded the injector on/off but did not see the subsequent change in electrical current. An example of an injector control circuit wiring diagram. Brand: NANA-AUTO. Currently unavailable. We don't know when or if this item will be back in stock. OEM: 01F002A. Fit for: Peugeot. Easy Installation: Easy to install and stable characteristics. Good quality: Constructed from high quality material,Durable and long lifetime guaranteed. Fast Delivery: Delivery as soon as possible within 7-15 The ECM uses the fuel rail pressure sensor to continuously monitor fuel pressure. If the ECM detects a problem, such as an unexpected increase or decrease in fuel pressure, or excessive or insufficient fuel pressure, that is, higher or lower than commanded, it will set diagnostic trouble code (DTC), DTC P0089 – “Fuel Pressure Regulator Open in the wiring to the injector; Short in the wiring to the injector; Bad PCM; Possible Solutions. First, using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector. Check for voltage at the fuel injector connector. It should have 10 volts or more. Visually check the connector for damage or broken Regarding a problem with an injector there are various solutions based on your concerns, here they are: Dirty injector: You can clean the injectors of your Alfa Romeo Giulia, do not hesitate to consult our content on this subject to get the process. If it doesn’t work, you will have to change them. Leaky injector: The change and the purchase The HP pump ramps up fuel pressure as high as 23,000 psi, depending on application. The ECM (engine control module) monitors fuel pressure for at least a couple of reasons. First, fuel pressure is important to modulate fuel injector pulse width. Generally speaking, higher fuel pressure requires less pulse width to get the same amount of fuel. The ECM monitors the status of the fuel injector circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the fuel injector control circuit is open for greater than 2 s. P0204 Code - Injector Circuit Malfunction Cylinder 4 If the ECM detects that fuel pressure isn’t rising sufficiently on command, it will set a diagnostic trouble code, DTC P0087, “Fuel Rail/System Pressure – Too Low,” and illuminate the malfunction indicator lamp (MIL). Concurrent DTCs may include cylinder misfire, air-fuel ratio sensor, or fuel trim codes. Ouch. The problem is that if one injector is failing then the other three are likely to follow pretty quickly. It's worth considering a chemical treatment firstly. In some instances these have worked very well indeed and the £20 it'll cost is a tiny fraction of the price of a set of injectors or even the price of a full injector overhaul. AqNet.