• Code: 3900
• Description: Backup memory read/write error (ISC PWB)
  Read and write data does not match.
• Causes: Defective backup memory or PWB.
• Remedy: Replace the ISC PWB and check for correct operation.

• Code: 4001
• Description: Polygon motor (K) steadystate error
  The rated speed signal detected the stability OFF continuously for 1 s after the polygon motor (K) stabilizes.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (K) and LSU connect PWB(YC5) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (K).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4002
• Description: Polygon motor (C) steadystate error
  The rated speed signal detected the stability OFF continuously for 1 s after the polygon motor (C) stabilizes.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (C) and LSU connect PWB(YC6) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (C).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4003
• Description: Polygon motor (M) steadystate error
  The rated speed signal detected the stability OFF continuously for 1 s after the polygon motor (M) stabilizes.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (M) and LSU connect PWB(YC7) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (M).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4004
• Description: Polygon motor (Y) steadystate error
  The rated speed signal detected the stability OFF continuously for 1 s after the polygon motor (Y) stabilizes.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (Y) and LSU connect PWB(YC8) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (Y).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4011
• Description: Polygon motor (K) startup error
  Polygon motor (K) is not stabilized within 10 s since the motor is activated.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (K) and LSU connect PWB(YC5) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (K).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4012
• Description: Polygon motor (C) startup error
  Polygon motor (C) is not stabilized within 10 s since the motor is activated.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (C) and LSU connect PWB(YC7) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (C).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.

• Code: 4013
• Description: Polygon motor (M) startup error
  Polygon motor (M) is not stabilized within 10 s since the motor is activated.
• Causes: Defective connector cable or poor contact in the connector. Defective motor. Defective 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. Laser scanner unit (M) and LSU connect PWB(YC6) LSU connect PWB and engine PWB (YC12)
  Defective motor. Replace the Laser scanner unit (M).
  Defective PWB. Replace the engine PWB or LSU connect PWB and check for correct operation.