What does it mean?
The days of carburetors are long gone. Electronic fuel injection has been implemented in cars since the 1980s. Fuel injection offers more precise control over the fuel distribution. This results in better economy, better performance and reduced emissions. One of the main components in a modern fuel system is the fuel injector. When the solenoid inside a fuel injector is energized, it lifts a valve off inside the injector and fuel is sprayed into the engine.
Typically, there is always battery power at one of the two injector terminals. When injection is required, the powertrain control module (PCM) driver grounds the other terminal. This completes the circuit and fuel is sprayed into the cylinder. A fuel injector Two of the most common injector driver designs are the “saturated switch” and the “peak and hold”. With the saturated switch, maximum current is applied to the injector while it is opened (pulsed).
On the other hand, the peak and hold design allows maximum current to flow just long enough to open the injector. After that, the current is reduced to the amount needed to hold the injector open. The code P0201 stands for Injector 1 – Circuit Malfunction. This means that the PCM had detected a malfunction in the first 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