What is Komatsu PC220-8M0 Fault Code DW45KB?

Fault Code DW45KB on the Komatsu PC220-8M0 indicates a communication error between the Engine Control Module (ECM) and the Hydraulic Control Module (HCM), specifically related to the multiplexed data transmission system. This code typically signals an interruption or degradation in the Controller Area Network (CAN) bus communication that allows critical machine systems to share operational data in real-time.

This fault is particularly critical on the PC220-8M0 because the ECM and HCM must constantly communicate to coordinate engine power output with hydraulic demand. When this communication fails, the machine cannot properly match engine response to operator inputs, resulting in reduced productivity and potential component damage due to uncoordinated system operation.

Common Symptoms

When DW45KB is active, operators typically experience:

• Warning lights illuminated on the monitor panel, specifically the caution or action indicator related to machine malfunction
• Reduced engine power or inability to reach full RPM under load conditions
• Sluggish hydraulic response or inconsistent boom/arm/bucket speed despite proper joystick input
• Intermittent loss of function where the machine works normally, then suddenly enters a derated state
• Error messages on the multi-information display indicating communication failure between control systems

Potential Causes

The most common technical causes for DW45KB on used PC220-8M0 excavators include:

• CAN bus wiring harness damage at known rub points near the engine-to-main frame harness connector, particularly where cables pass through the swing bearing area
• Corroded or loose connector pins at the X1 or X2 connectors on either the ECM or HCM due to moisture intrusion
• Damaged termination resistors within the CAN bus network (120-ohm resistors that maintain signal integrity)
• ECM or HCM internal failure, though less common, particularly in machines with high operating hours
• Voltage irregularities from failing batteries or alternator issues affecting module communication power supply

How to Troubleshoot and Fix Code DW45KB

Step 1: Visual Inspection Begin by thoroughly inspecting the main wiring harness between the ECM (located behind the operator cab) and HCM (mounted near the hydraulic pump). Look specifically for abraded insulation, pinched wires, or signs of previous repairs. On used excavators, check connector boots for cracks that allow moisture penetration.

Step 2: Electrical Testing Using a digital multimeter, check CAN-High and CAN-Low bus voltage at the ECM connector. With ignition on and engine off, you should read approximately 2.5V on both lines. Check termination resistance by disconnecting both modules and measuring resistance between CAN-H and CAN-L terminals—it should read approximately 60 ohms (two 120-ohm resistors in parallel).

Step 3: Advanced Diagnostics Connect Komatsu KOMTRAX diagnostic software or an equivalent CAN bus analyzer to monitor real-time communication. Look for message dropout patterns or error frames. Inspect all ground connections (G101, G102) for corrosion, as poor grounding frequently causes intermittent communication faults in high-hour machines.

Step 4: Component Replacement If testing reveals damaged wiring, repair using proper CAN bus-rated twisted pair cable with appropriate shielding. Clean all connector pins with electrical contact cleaner and apply dielectric grease. Replace termination resistors if resistance values are out of specification. Only replace ECM or HCM after confirming all wiring and connections are verified functional.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu PC220-8M0 service manual and consider engaging a certified Komatsu technician for complex electrical diagnostics, especially when working with used machinery where previous unauthorized repairs may complicate diagnosis.