• Code: 7800
• Description: Broken outer temperature sensor 1 wire
  The sensor input sampling is greater than 255.
• Causes: Defective connector cable or poor contact in the connector.
  Defective outer temperature sensor 1.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Outer temperature sensor 1 and front PWB (YC16) Front PWB (YC2) and engine PWB (YC10)
  Defective outer temperature sensor 1. Replace outer temperature sensor 1.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7810
• Description: Short-circuited outer temperature sensor 1
  The sensor input sampling is less than 0.
• Causes: Defective connector cable or poor contact in the connector.
  Defective outer temperature sensor 1.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Outer temperature sensor 1 and front PWB (YC16) Front PWB (YC2) and engine PWB (YC10)
  Defective outer temperature sensor 1. Replace outer temperature sensor 1.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7901
• Description: Drum K EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drum PWB K.
  
  
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum PWB K and front PWB (YC7) Front PWB (YC2) and engine PWB (YC10)
  Defective drum PWB K. Replace the drum unit K.

• Code: 7902
• Description: Drum C EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drum PWB C.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum PWB C and front PWB (YC12) Front PWB (YC2) and engine PWB (YC10)
  Defective drum PWB C. Replace the drum unit C.

• Code: 7903
• Description: Drum M EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drum PWB M.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum PWB M and front PWB (YC10) Front PWB (YC2) and engine PWB (YC10)
  Defective drum PWB M. Replace the drum unit M.

• Code: 7904
• Description: Drum Y EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drum PWB Y.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum PWB Y and front PWB (YC14) Front PWB (YC2) and engine PWB (YC10)
  Defective drum PWB Y. Replace the drum unit Y.

• Code: 7911
• Description: Developer unit K EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective developer unit K.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Developer unit K and front PWB (YC9) Front PWB (YC2) and engine PWB (YC10)
  Defective developer unit K. Replace the developer unit K.

• Code: 7912
• Description: Developer unit C EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective developer unit C.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Developer unit C and front PWB (YC13) Front PWB (YC2) and engine PWB (YC10)
  Defective developer unit C. Replace the developer unit C.