OBD-II Trouble Code Description for P0203 GMC

Injector Circuit/Open – Cylinder 3

What does this mean?

OBD2 Code P0203 GM definition:
P0203 GM 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.

Symptoms

Possible sumptoms of OBD code P0203 GM
The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.

Causes

Possible causes of OBD code P0203 GM
The causes of a P0203 GM 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 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 wires. Visually check the injector for damage. If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector. At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you’re not sure, do not attempt) The injector should activate Replace the injector 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 wires. Visually check the injector for damage. If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector. At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you’re not sure, do not attempt) The injector should activate Replace the injector