Kubota P062B – Engine ECU: Internal injector drive circuit abnormality open circuit / Injector drive IC error

The engine computer has detected an open circuit in the fuel injector wiring for cylinders #1, 2, 3, or 4, or it has detected an internal failure (such as an internal IC clock error) within the module's injector drive circuitry. This condition typically forces the engine to stop, limits output, causes severe vibration, and halts fuel injection.

• L3901
• L4701
• L6060
• MX series
• SSV75P
• Carrier generators
• Bobcat loaders
• V2403-CR-TE4
• V3800-TIEF4
• V3307
• D1803

1. 1

   Check battery voltage to ensure it is normal (minimum 10V) with the ignition switch ON

2. 2

   Inspect the main ground connection for the Engine ECU for poor contact or corrosion

3. 3

   Inspect the wiring harness between the Engine ECU and the fuel injectors for open circuits, broken wires, loose plugs, or corrosion

4. 4

   Test individual fuel injectors to ensure they are not shorted or open

1. 1

   Turn off ignition

   Turn the ignition switch to the "OFF" position.

2. 2

   Test battery

   Test the battery to ensure it is fully charged and delivering over 10 volts under load.

3. 3

   Clean ground connection

   Locate the main ground strap for the Engine ECU (often near the fuel tank or engine block) and clean the contacts to ensure a solid connection.

4. 4

   Check wiring harness continuity

   Disconnect the wiring harness at the injectors and the ECU. Use a digital multimeter to check for continuity and ensure there are no open circuits on the lines for cylinders 1, 2, 3, and 4.

5. 5

   Test injector resistance

   Measure the resistance across the pins of each fuel injector to verify they are within OEM specifications.

6. 6

   Diagnose ECU failure

   If the wiring harness and injectors test perfectly fine, the fault is an internal failure of the Engine ECU's injector drive IC.

7. 7

   Replace or rebuild ECU

   Remove the faulty Engine ECU and either send it out for a rebuild service or replace it with a new/remanufactured unit.