• Code: 7252
• Description: Short-circuited developer thermistor C
  The sensor input sampling is less than 69.
• Causes: Defective connector cable or poor contact in the connector
  Defective developer thermistor C.
  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. Developer unit C and front PWB (YC13) Front PWB (YC2) and engine PWB (YC10)
  Defective developer thermistor C. Replace developer unit C.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7253
• Description: Short-circuited developer thermistor M
  The sensor input sampling is less than 69.
• Causes: Defective connector cable or poor contact in the connector
  Defective developer thermistor M.
  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. Developer unit M and front PWB (YC11) Front PWB (YC2) and engine PWB (YC10)
  Defective developer thermistor M. Replace developer unit M.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7254
• Description: Short-circuited developer thermistor Y wire
  The sensor input sampling is less than 69.
• Causes: Defective connector cable or poor contact in the connector.
  Defective developer thermistor Y.
  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. Developer unit Y and front PWB (YC15) Front PWB (YC2) and engine PWB (YC10)
  Defective developer thermistor Y. Replace developer unit Y.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7301
• Description: Toner hopper motor K error
  When the toner hopper motor K is driven, toner hopper sensor K does not turn on within 200 ms. This error is detected 15 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drive transmission system of motor
  Defective toner hopper sensor K.
  Defective toner hopper motor K.
  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. Toner hopper motor K and retainer PWB (YC4) Retainer PWB (YC3) and front PWB (YC6) Front PWB (YC3) and engine PWB (YC7)
  Defective drive transmission system of motor. Check if the gears rotate smoothly. If not, grease the bushes and gears. Check for broken gears and replace if any.
  Defective toner hopper sensor K. Replace the toner hopper sensor K.
  Defective toner hopper motor K. Replace the toner hopper motor K.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7302
• Description: Toner hopper motor C error
  When the toner hopper motor C is driven, toner hopper sensor C does not turn on within 200 ms. This error is detected 15 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drive transmission system of motor
  Defective toner hopper sensor C.
  Defective toner hopper motor C.
  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. Toner hopper motor C and retainer PWB (YC4) Retainer PWB (YC3) and front PWB (YC6) Front PWB (YC3) and engine PWB (YC7)
  Defective drive transmission system of motor. Check if the gears rotate smoothly. If not, grease the bushes and gears. Check for broken gears and replace if any.
  Defective toner hopper sensor C. Replace the toner hopper sensor C.
  Defective toner hopper motor C. Replace the toner hopper motor C.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7303
• Description: Toner hopper motor M error
  When the toner hopper motor M is driven, toner hopper sensor M does not turn on within 200 ms. This error is detected 15 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drive transmission system of motor.
  Defective toner hopper sensor M.
  Defective toner hopper motor M.
  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. Toner hopper motor M and retainer PWB (YC4) Retainer PWB (YC3) and front PWB (YC6) Front PWB (YC3) and engine PWB (YC7)
  Defective drive transmission system of motor. Check if the gears rotate smoothly. If not, grease the bushes and gears. Check for broken gears and replace if any.
  Defective toner hopper sensor M. Replace the toner hopper sensor M.
  Defective toner hopper motor M. Replace the toner hopper motor M.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7304
• Description: Toner hopper motor Y error
  When the toner hopper motor Y is driven, toner hopper sensor Y does not turn on within 200 ms. This error is detected 15 times successively.
• Causes: Defective connector cable or poor contact in the connector.
  Defective drive transmission system of motor.
  Defective toner hopper sensor Y.
  Defective toner hopper motor Y.
  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. Toner hopper motor Y and retainer PWB (YC4) Retainer PWB (YC3) and front PWB (YC6) Front PWB (YC3) and engine PWB (YC7)
  Defective drive transmission system of motor. Check if the gears rotate smoothly. If not, grease the bushes and gears. Check for broken gears and replace if any.
  Defective toner hopper sensor Y. Replace the toner hopper sensor Y.
  Defective toner hopper motor Y. Replace the toner hopper motor Y.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7401
• Description: Developer unit K type mismatch error
  Absence of the developer unit K is detected.
• Causes: Defective connector cable or poor contact in the connector.
  Different type of the developer unit is installed.
• 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)
  Different type of the developer unit is installed. Install the correct developer unit.