What is Komatsu PC220-8 Fault Code DW45KB?

Fault Code DW45KB on the Komatsu PC220-8 excavator indicates a communication error between the engine ECM (Engine Control Module) and the machine's main monitor or display unit. This diagnostic trouble code signals that data transmission has been interrupted or corrupted between these critical control systems.

This fault specifically affects the CAN (Controller Area Network) bus communication that allows the engine controller to send operational data to the operator's display panel. On the PC220-8, this communication pathway is essential because it transmits critical engine parameters including RPM, temperature, pressure readings, and active fault codes. When this communication link fails, the operator loses vital real-time diagnostic information, and the machine's electronic systems cannot properly coordinate, potentially triggering protective derate modes or limiting functionality.

Common Symptoms

• Warning triangle or communication error icon displayed on the main monitor screen
• Loss of engine parameter displays – RPM, coolant temperature, or fuel level gauges may show zero or freeze
• Intermittent or complete monitor blackout while the engine continues running normally
• Secondary fault codes appearing due to the ECM's inability to communicate system status
• Machine may enter limp mode with reduced hydraulic performance as a safety precaution

Potential Causes

The DW45KB code typically stems from issues common in used excavators with accumulated operating hours:

• Damaged or corroded CAN bus wiring harness – particularly at flex points near the engine mount or cab pivot where vibration causes wire chafing
• Loose or corroded connectors at the ECM (located near the battery box) or monitor junction points behind the operator panel
• Failed termination resistor on the CAN network causing signal reflection and data corruption
• ECM or monitor unit internal fault – less common but possible in high-hour machines
• Voltage supply issues to either the ECM or monitor due to poor grounding or battery connection problems
• Water intrusion into connector pins, especially on machines operated in wet conditions

How to Troubleshoot and Fix Code DW45KB

Step 1: Visual Inspection of Harnesses and Connectors

Begin by inspecting the communication harness running from the engine compartment to the cab. On used PC220-8 excavators, check the harness routing near the turntable interface where constant rotation causes wear. Look for abraded wire insulation, particularly on the twisted-pair CAN-H and CAN-L wires (typically yellow and green). Disconnect and inspect all connectors along this path for corrosion, bent pins, or moisture.

Step 2: Test CAN Bus Voltage and Resistance

Using a digital multimeter, measure the resistance between CAN-H and CAN-L terminals at the ECM connector (typically pins 26 and 34 on the PC220-8). You should read approximately 60 ohms with the ignition off, indicating proper termination resistors. With ignition on and engine off, measure voltage on each CAN line – both should read approximately 2.5 volts relative to ground. Significant deviation indicates a short, open circuit, or failed termination.

Step 3: Check Power Supply and Grounding

Verify the ECM and monitor are receiving proper voltage (typically 24V on Komatsu equipment). Check all ground connections, especially the ECM ground strap to the chassis. On high-hour used excavators, ground connections frequently corrode, creating intermittent communication failures.

Step 4: Use Komatsu Diagnostic Software

Connect Komatsu KOMTRAX or PC-compatible diagnostic software (KDW600 series) to access detailed communication logs. This will show exactly where the communication breakdown occurs and whether other controllers on the network are affected.

Step 5: Component Replacement

If diagnostics isolate the fault to a specific component, replace the harness, connector, or control module as needed. For used machines, always apply dielectric grease to reconnected plugs to prevent future corrosion.

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Disclaimer: This guide provides general troubleshooting information for the Komatsu PC220-8. Always consult the official Komatsu service manual for your specific machine serial number, and consider professional diagnosis by a certified Komatsu technician for complex electrical issues or warranty concerns.