P0203 - Cylinder 3 Injector Circuit Malfunction
means that the PCM detected a fault in the injector or the wiring to the injector. It monitors the injector and when the injector is activated, the PCM expects to see the voltage pulled "low" or close to zero. When the injector is switched off, the PCM expects to see a voltage that is close to battery voltage or "high". If it doesn't see the expected voltage the PCM will set this code. The PCM also monitors resitance in the circuit. If the resistance is excessively low or high it will set this code.
The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.
The causes of a P0203 engine light code could be any of the following:
Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
Open in the wiring to the injector
Short in the wiring to the injector
Bad PCMHope this helps and just keep in mind that your feedback is important
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