Kubota P2151 – Engine ECU: No. 2 & 3 cylinder injector short to +B

The engine control system has detected a short circuit to battery voltage (+B) or a short to ground in the injector drive circuit specifically controlling the fuel injectors for cylinders No. 2 and No. 3. This often inhibits DPF regeneration and causes insufficient engine output, large engine vibrations, worsening exhaust gas performance, or engine shutdown.

• V2403-CR-TE4B
• V3307
• V3800-CR-TE4
• V3800-CR-TIE4
• M5040
• M6040
• M7040
• M6060
• M7060
• KX080-4
• SSV75
• SVL75-2
• SVL95
• Baroness LM3210A

1. 1

   Verify the battery is fully charged and the alternator is outputting correct voltage, as the ECU sets this DTC under the precondition that battery voltage is normal.

2. 2

   Visually inspect the engine wiring harness leading from the Engine ECU to the No. 2 and No. 3 cylinder injectors for chafed wires, melted insulation, or pinched harnesses.

3. 3

   Use a multimeter to test the continuity and resistance of the injector drive circuit for cylinders 2 and 3, including testing for continuity between the injector harness pins and the battery positive terminal.

4. 4

   Test the internal resistance of the No. 2 and No. 3 injectors to determine if the short is internal to the injector solenoid itself.

1. 1

   Turn the ignition key to the "OFF" position and disconnect the negative battery cable to prevent electrical damage.

2. 2

   Clean the area around the fuel rail and injectors to prevent debris from entering the fuel system.

3. 3

   If the diagnostic checks revealed a damaged wiring harness, repair the damaged wires using proper soldering and heat-shrink techniques, or replace the engine wiring harness entirely.

4. 4

   If the harness is intact but an injector is internally shorted, remove the high-pressure fuel lines connected to the faulty injector(s).

5. 5

   Remove the hold-down clamps and extract the faulty No. 2 and/or No. 3 injector(s).

6. 6

   Install the new OEM injector(s) with new seals/O-rings. Hand-tighten connections before torquing to factory specifications.

7. 7

   Use a diagnostic scan tool to program the new injector's QR (IQA) code into the Engine ECU so it can adjust the injection timing and fuel quantity.

8. 8

   Reconnect the battery, prime the fuel system, clear the P2151 fault code from the ECU, and run the engine to check for leaks and verify the vibration/power loss is resolved.