Kubota P2304 – Engine Control Module (ECM / ECU): Spark Coil #2 Primary Short-to-Power

The engine computer has detected an abnormally high voltage or a short-to-power condition in the primary control circuit for Ignition Coil #2 (Cylinder 2). This triggers when battery voltage is between 10.0 and 16.0 volts, the engine is cranking or running, and there is a short to power in the wiring harness or an internal short in the primary coil.

• WG1605
• WG1903
• WG2503
• WG3800

1. 1

   Inspect the wiring harness and connector at Ignition Coil #2 for chafed wires, melted insulation, or oil/water intrusion that could cause a short to power.

2. 2

   With the key ON (engine OFF), back-probe the coil control wire. If it shows constant battery voltage (~12V), the harness is shorted to power between the ECM and the coil.

3. 3

   Swap Ignition Coil #2 with Ignition Coil #1 (or another known-good cylinder), clear the codes, and run the engine. If the code changes to the new cylinder, the ignition coil has an internal short. If P2304 returns on Cylinder #2, the issue is in the wiring harness or the ECM driver.

1. 1

   Disconnect the battery

   Turn off the engine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Locate Ignition Coil #2

   Locate Ignition Coil #2 on the top of the engine valve cover.

3. 3

   Disconnect the electrical connector

   Depress the locking tab and disconnect the electrical connector from the ignition coil.

4. 4

   Remove the retaining bolt

   Remove the retaining bolt holding the ignition coil in place.

5. 5

   Remove the ignition coil

   Pull the ignition coil straight up and out of the spark plug tube. (Note: It is highly recommended to inspect and/or replace the spark plug while the coil is removed).

6. 6

   Apply dielectric grease

   Apply a small amount of dielectric grease to the boot of the new ignition coil.

7. 7

   Install the new ignition coil

   Push the new ignition coil firmly down into the spark plug tube until it seats fully onto the spark plug terminal.

8. 8

   Reinstall the retaining bolt

   Reinstall and tighten the retaining bolt.

9. 9

   Reconnect the electrical connector

   Reconnect the electrical connector until it clicks securely.

10. 10

    Reconnect the battery and test

    Reconnect the battery, clear the DTCs with a diagnostic scanner, and test-run the engine to ensure the misfire and fault code are resolved.