• Code: U1-01
• Description: Battery trouble
  RTC backup battery voltage fall
• Causes: 1) Battery life 2) Battery circuit abnormality
• Remedy: Check to confirm that the battery voltage is about 2.5V or above. Replace the battery.

• Code: U2-00
• Description: MFP EEPROM read/write error
• Causes: MFPC PWB EEPROM trouble EEPROM socket contact trouble MFPC PWB trouble Strong external noises.
• Remedy: Replace the MFPC PWB EEPROM. Replace the MFPC PWB. (Refer to the pages on the necessary works after replacing the MFPC PWB in the Service Manual, and perform the works.) Check the power environment.

• Code: U2-05
• Description: HDD/MFPC PWB SRAM contents inconsistency (23cpm machine)
  The HDD or the MFPC PWB installed is improper. (Erroneous detection of account management data)
• Causes: The HDD was replaced. The MFPC PWB was replaced. HDD trouble MFPC PWB trouble
• Remedy: (Refer to the pages on the necessary works after replacing the HDD and the MFPC PWB in the Service Manual, and perform the works.) Use SIM16 to cancel the error.

• Code: U2-05
• Description: Erroneous detection of account management data / HDD internal authentication DB table error (26/31/36cpm machine)
• Causes: The HDD internal authentication DB table is broken. After detection of the broken authentication DB table, the machine is rebooted to rebuild the authentication table. This error can be confirmed only by the error history of SIM22-4. If frequent occurrence of this error is found, the following devices may possibly be damaged. HDD trouble MFPC PWB trouble
• Remedy: Check the HDD, and replace if necessary. Check the MFPC PWB, and replace if necessary. When replacing the HDD and the MFPC PWB, refer to "Necessary works and procedures for replacement of HDD and MFPC PWB" and perform the necessary procedures. If this error does not occur frequently, the above procedure is not required.

• Code: U2-10
• Description: MFPC PWB SRAM user authentication index check sum error
• Causes: SRAM user index information (user authentication basic data) check sum error. MFPC PWB SRAM trouble. MFPC PWB trouble. Strong external noises.
• Remedy: Use SIM16 to cancel the error. (Index information data in the HDD are transferred to the SRAM.) Replace the MFPC PWB. (Refer to the pages on the necessary works after replacing the MFPC PWB in the Service Manual, and perform the works.)

• Code: U2-11
• Description: MFPC PWB EEPROM counter check sum error
• Causes: MFPC PWB EEPROM trouble EEPROM socket contact trouble MFPC PWB trouble Strong external noises.
• Remedy: Use SIM16 to cancel the error. (The previous writing data (about the latest 8 sheets) are written into the EEPROM.) Replace the MFPC PWB. (Refer to the pages on the necessary works after replacing the MFPC PWB in the Service Manual, and perform the works.)

• Code: U2-24
• Description: MFPC PWB SRAM memory user authentication counter check sum error
• Causes: MFPC PWB SRAM trouble MFPC PWB trouble Strong external noises.
• Remedy: Use SIM16 to cancel the error. (The check sum error detection data are calculated again to reset the proper check sum data.) Replace the MFPC PWB. (Refer to the pages on the necessary works after replacing the MFPC PWB in the Service Manual, and perform the works.)

• Code: U2-30
• Description: MFPC PWB and PCU PWB manufacturing No. data inconsistency
  Inconsistency between the manufacturing No. saved in the PCU PWB and that in the MFPC PWB.
• Causes: When replacing the PCU PWB or the MFPC PWB, the EEPROM which was mounted on the PWB before replacement is not mounted on the new PWB. MFPC PWB trouble PCU PWB trouble
• Remedy: Check that the EEPROM is properly set. Check to confirm that the EEPROM which was mounted on the PWB before replacement is mounted on the new PWB. Replace the MFPC PWB. (Refer to the pages on the necessary works after replacing the MFPC PWB in the Service Manual, and perform the works.) Replace the PCU PWB.