What is Komatsu PC210LC-8 Fault Code DW45KB?

Fault Code DW45KB indicates a communication error between the engine controller (ECM) and the hydraulic controller (CLSS controller) on the Komatsu PC210LC-8 excavator. This Diagnostic Trouble Code (DTC) specifically points to a failure in the Controller Area Network (CAN) data transmission between these two critical control modules.

The CLSS (Closed Center Load Sensing System) on the PC210LC-8 requires constant communication with the engine ECM to optimize hydraulic performance and fuel efficiency. When this communication breaks down, the excavator cannot properly coordinate engine output with hydraulic demand, directly impacting machine productivity and operational costs. This fault is particularly critical because it affects the integrated control system that makes Dash-8 series Komatsu excavators efficient under varying load conditions.

Common Symptoms

• Error message displayed on the multi-function monitor showing "CAN communication error" or similar warning
• Reduced hydraulic response and sluggish operation, as the system defaults to a safe, non-optimized mode
• Increased fuel consumption because the engine and hydraulic systems cannot work in coordination
• Yellow warning lamp illuminated on the instrument panel, indicating a system malfunction requiring attention
• Intermittent loss of certain functions such as auto-idle or power mode selection

Potential Causes

The most common causes of DW45KB on used PC210LC-8 excavators include:

• Damaged or corroded CAN bus wiring harness between the engine compartment and cab, particularly at flex points near the swing bearing where repeated rotation causes wire fatigue
• Failed termination resistor in the CAN communication circuit (120-ohm resistor failure is common on machines with 5,000+ hours)
• Loose or corroded connector terminals at either the engine ECM (located under the engine cover) or the CLSS controller (mounted in the cab)
• ECM or CLSS controller internal failure, more common in high-hour used machines exposed to excessive vibration or heat
• Water intrusion into controller connectors, especially on machines operated in wet environments or those with damaged cab sealing

How to Troubleshoot and Fix Code DW45KB

Step 1: Initial Inspection and Connector Check

Begin by visually inspecting all CAN bus connectors at both the engine ECM and CLSS controller. Clean any corrosion with electrical contact cleaner and ensure all connector locks are fully engaged. On used excavators, pay special attention to the main harness routing through the swing post area—this is a known wear point on the PC210LC-8.

Step 2: CAN Bus Circuit Testing

Using a digital multimeter, check the CAN-High and CAN-Low lines for proper voltage (typically 2.5V baseline with fluctuation during communication). With the ignition on but engine off, measure resistance between CAN-High and CAN-Low terminals—you should see approximately 60 ohms, indicating proper termination. A reading near 120 ohms suggests one termination resistor has failed (open circuit).

Step 3: Harness Continuity and Isolation Testing

Disconnect both controllers and test the wiring harness continuity between ECM and CLSS controller CAN pins. Each wire should show less than 5 ohms resistance. Also verify no shorts to ground (infinite resistance to chassis ground). For used machines, flex the harness while testing to identify intermittent breaks from wire fatigue.

Step 4: Component Replacement and Software Verification

If wiring tests pass, the fault likely resides in a controller. Use Komatsu KOMTRAX or diagnostic software to isolate which controller isn't responding. Replace the faulty ECM or CLSS controller with OEM or verified compatible units. After replacement, clear codes and verify communication is restored through live data monitoring.

Disclaimer: This guide provides general troubleshooting information. Complex electrical diagnostics on heavy equipment should be performed by qualified technicians with appropriate tools and safety equipment. Always consult the official Komatsu service manual for your specific machine serial number before performing repairs.