Kubota P1613 – Engine Control Module (ECM) / ECU: Microprocessor Failure-RTI 2

This is a non-emissions-related fault indicating an internal microprocessor error. The code sets when the ECM's internal electronics detect a fault condition associated with its internal circuitry, memory, or internal actuator.

• WG1605-G-E3
• WG1605-L-E3
• WG1605-GL-E3
• WG1605-N-E3
• WG972
• D1105-E3B
• WG-LSI

1. 1

   Check the 5V external reference circuits (5Vext1 or 5Vext2) to ensure they are within the 4.60V to 5.40V range

2. 2

   Inspect the main engine wiring harness for a direct short to 12V power or a short to ground

3. 3

   Check for concurrent sensor failures, specifically a fuel temperature sensor failure or a Direct Electronic Pressure Regulator (DEPR) internal failure

4. 4

   Verify battery voltage is stable between 12.4–14.6 V and inspect the ECM connector for corrosion, bent pins, or loose connections

1. 1

   Clear and Retest

   Connect the Kubota EDIS or KGST diagnostic service tool to the machine. Attempt to manually erase the code. Cycle the key off, then back to the 'Key On' position. If the code does not return, it may have been a transient voltage spike.

2. 2

   Harness Isolation

   If the code returns immediately upon Key On, disconnect the ECM and use a multimeter to test the harness pins for shorts to ground or voltage.

3. 3

   Replace the ECM

   If the wiring harness tests good, the 5V reference circuits are not shorted, and the code persists, the internal microprocessor has permanently failed (Faulty ECU). You must replace the Engine Control Module.

4. 4

   Reprogramming

   Install the new ECM. Note that depending on the machine, the new ECM may need to be flashed or calibrated with the specific equipment manufacturer's software parameters to communicate with the machine's CAN bus.