Kubota P0203 – ECM: Injector Circuit/Open - Cylinder 3

The Engine Control Module (ECM) has detected an open circuit condition in the electrical circuit for the fuel injector on cylinder number 3. The ECM controls the fuel injectors by providing a ground signal and expects to see a specific voltage and resistance range. If it does not detect the expected electrical response when commanding the injector to open, it logs this code. This indicates an electrical problem, such as a broken wire, disconnected plug, or failed internal injector coil, rather than a mechanical failure like a clog.

• SVL90-2
• SVL95-2S
• SVL95-2SC
• SVL97-2
• SVL97-2C
• M5-091
• M5-111
• M8560 series
• M9960 series

1. 1

   Visually inspect the wiring harness and electrical connector at the cylinder 3 fuel injector for damage, cracked insulation, corrosion, loose connections, or oil/fuel saturation.

2. 2

   Verify battery voltage is present at one of the terminals on the injector connector with the key in the 'on' position using a multimeter or 12-volt test light.

3. 3

   Check for an ECM ground pulse signal at the other terminal using a noid light or multimeter while the engine is cranking or running.

4. 4

   Measure the injector coil resistance across its two terminals (normal range for a common rail injector is 0.2 to 1.0 Ω). An infinite reading indicates an internal open circuit.

5. 5

   Perform a common rail injector leak-off test to check mechanical health if electrical checks are inconclusive.

1. 1

   Access and identify injector

   Safely gain access to the engine's fuel rail (removing covers if necessary) and locate the fuel injector for cylinder number 3.

2. 2

   Repair wiring or connector

   If diagnostic checks revealed wiring issues, clean corroded terminals, repair broken wires, or replace a damaged connector pigtail.

3. 3

   Replace fuel injector

   If the injector coil has infinite resistance (open circuit), replace the injector. Relieve high-pressure fuel system pressure first. Disconnect the electrical connector and high-pressure line, remove the hold-down clamp, and extract the injector. Install the new injector with a new sealing washer and torque the hold-down clamp to manufacturer specifications.

4. 4

   Clear fault codes

   Use a diagnostic scan tool to clear the P0203 fault code from the ECM's memory.

5. 5

   Verify repair

   Start the engine and verify the misfire is gone, idle is smooth, the check engine light remains off, and there are no fuel leaks around the new injector.