P0203 Code

Definition of Trouble Code P0204

Trouble code P0204 refers to a malfunction in the fuel injector circuit for cylinder 4. This code indicates that the Engine Control Module (ECM) has detected an issue with the electrical circuit that controls the fuel injector for the fourth cylinder. A malfunction in this circuit can lead to poor engine performance, reduced fuel efficiency, and increased emissions.

Diagnosing Trouble Code P0204

Before starting the diagnosis process, gather the necessary tools and equipment, such as an OBD-II scanner, multimeter, and a repair manual specific to your vehicle. Follow these steps to diagnose the problem:

  1. First, connect the OBD-II scanner to the vehicle's diagnostic port and retrieve any stored trouble codes and freeze frame data. This information can be helpful in identifying any additional issues that may be present.

  2. Clear the codes and take the vehicle for a test drive to see if the code reappears. If the P0204 code returns, proceed to the next step.

  3. Turn off the vehicle and locate the fuel injector for cylinder 4, using your vehicle's repair manual as a guide.

  4. Visually inspect the fuel injector wiring harness and connectors for signs of damage, corrosion, or loose connections. Repair or replace any damaged components as needed.

  5. Using a multimeter, check the resistance of the fuel injector. Compare the reading to the manufacturer's specifications found in the repair manual. If the resistance is out of spec, replace the fuel injector.

  6. Test the voltage at the fuel injector connector with the ignition on and the engine off. The voltage should be within the range specified in the repair manual. If the voltage is incorrect, check the wiring and connectors between the fuel injector and the ECM for damage or loose connections.

  7. If all the previous steps have not revealed the issue, it may be necessary to check the ECM itself for faults. This should be done by a qualified technician as it requires specialized equipment and expertise.

Repairing Trouble Code P0204

Once the issue has been diagnosed, follow these steps to repair the problem:

  1. Repair or replace any damaged wiring or connectors found during the diagnosis process.

  2. If the fuel injector resistance was out of spec, replace the faulty injector with a new one.

  3. If voltage issues were identified, repair any damaged wiring or connectors between the fuel injector and the ECM.

  4. In cases where the ECM is found to be faulty, have it replaced or repaired by a qualified technician.

  5. After completing the repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to ensure the problem is resolved.


Trouble code P0204 indicates a malfunction in the injector circuit for cylinder 4. By following the steps outlined above for diagnosing and repairing the issue, you can restore your vehicle's performance, improve fuel efficiency, and reduce emissions. It is important to address this issue promptly to avoid further damage to the engine or other components.

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