Kubota P1990 – Engine ECU: KBT-EEPROM check sum error

The Engine Control Unit (ECU) has detected a discrepancy or corruption in the checksum of its internal Electrically Erasable Programmable Read-Only Memory (EEPROM).

• V2403-CR-TE4B
• V2403-CR-TE5B
• V2403-CR-T
• V2607
• V3307
• V1505-CR-TE5
• 07-CR-E4B
• 07-CR-TE4B
• 07-CR-TIE4B
• L3901
• MX5800

1. 1

   Verify battery voltage is normal, fully charged, and connections are tight.

2. 2

   Cycle the ignition by turning the key switch to the OFF position, waiting, and then turning it to the RUN position.

3. 3

   Connect a computer to the Engine ECU and open the Kubota Diagmaster software.

4. 4

   Bring up the DTC screen and clear the P1990 code.

5. 5

   Monitor for return of the DTC to rule out an electromagnetic interference (EMI) spike or a transient voltage drop.

1. 1

   Confirm ECU Failure

   If the code cannot be cleared, the Engine ECU itself is defective.

2. 2

   Contact Dealer / Repair Service

   Immediately contact your local dealer for an EEPROM checksum error. The ECU cannot be repaired in the field.

3. 3

   Replace or Rebuild the ECU

   Send the ECU to a specialized heavy-equipment electronics repair facility to have the EEPROM repaired/cloned, or purchase a replacement ECU.

4. 4

   Reprogramming

   If a new ECU is installed, it must be flashed with the correct engine calibration file and the specific QR data for the fuel injectors using the Kubota Diagmaster tool.