• Code: U9 80
• Description: Communication trouble between MCU and the operation control PWB (Protocol error)
• Causes: Operation control PWB connector disconnection Operation control PWB MCU PWB harness failure
• Remedy: Check the connectors and harness of the operation control PWB and the MCU PWB. Check grounding of the machine.

• Code: U9 81
• Description: Communication trouble between MCU and the operation control PWB (Parity error)
• Causes: Operation control PWB connector disconnection Operation control PWB MCU PWB harness failure
• Remedy: Check the connectors and harness of the operation control PWB and the MCU PWB. Check grounding of the machine.

• Code: U9 82
• Description: Communication trouble between MCU and the operation control PWB (Overrun error)
• Causes: Operation control PWB connector disconnection Operation control PWB MCU PWB harness failure
• Remedy: Check the connectors and harness of the operation control PWB and the MCU PWB. Check grounding of the machine.

• Code: U9 84
• Description: Communication trouble between MCU and the operation control PWB (Framing error)
• Causes: Operation control PWB connector disconnection Operation control PWB MCU PWB harness failure
• Remedy: Check the connectors and harness of the operation control PWB and the MCU PWB. Check grounding of the machine.

• Code: U9 88
• Description: Communication trouble between MCU and the operation PWB (Time-out error)
• Causes: Operation control PWB connector disconnection Operation control PWB MCU PWB harness failure
• Remedy: Check the connectors and harness of the operation control PWB and the MCU PWB. Check grounding of the machine.