What is Komatsu PC110-8M0 Fault Code DW45KB?

Fault Code DW45KB on the Komatsu PC110-8M0 indicates a communication error between the Engine Control Module (ECM) and the Hydraulic Pump Control Unit (HPCU), specifically related to load-sensing system data transmission failure. This code is generated when the ECM cannot receive valid torque control signals from the hydraulic control system, disrupting the coordination between engine output and hydraulic demand.

This fault is critical for the PC110-8M0 because this model uses an advanced engine-pump matching system to optimize fuel efficiency and prevent engine overload. When communication fails, the excavator cannot properly regulate hydraulic flow based on engine capacity, leading to performance degradation and potential component damage. The PC110-8M0's CLSS (Closed-Center Load Sensing System) relies entirely on this data exchange to maintain smooth operation.

Common Symptoms

When fault code DW45KB is active, operators typically experience:

• Engine derate mode with noticeable power reduction, especially during combined operations (swing + boom lift)
• Illuminated malfunction warning lamp on the monitor panel with possible intermittent alarm buzzer
• Sluggish hydraulic response or inconsistent cycle times across all functions
• Engine RPM fluctuations under load, particularly when engaging multiple hydraulics simultaneously
• Monitor display showing reduced engine power output percentage (typically limited to 75-80% capacity)

Potential Causes

The most common technical reasons for DW45KB appearing on used PC110-8M0 excavators include:

• CAN bus communication harness damage between ECM and HPCU, particularly at the routing point near the left engine mount where vibration causes wire chafing
• Corroded or loose connector pins at the HPCU interface (connector C47), common in machines with 4,000+ operating hours
• HPCU internal solenoid valve failure affecting signal output quality, especially in machines operated in dusty environments
• ECM software version mismatch after component replacements using non-OEM or refurbished parts
• Voltage supply issues to the HPCU due to degraded main power harness or failing alternator (should maintain 24V ±2V)
• Failed shielding on CAN communication wires allowing electromagnetic interference from starter motor or alternator

How to Troubleshoot and Fix Code DW45KB

Step 1: Visual Inspection and Connector Verification Begin by inspecting the CAN bus harness routing from the ECM (located under the operator cab floor) to the HPCU (mounted on the hydraulic pump). Check for obvious damage, particularly where the harness passes through the bulkhead near the swing bearing. Remove connector C47 at the HPCU and inspect for corrosion, bent pins, or moisture intrusion—common in used excavators. Clean contacts with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing with Diagnostic Tools Using a digital multimeter, verify power supply to the HPCU at connector terminals (typically 24V on pin 1). Connect Komatsu KOMTRAX diagnostic software or compatible scan tool to read live data stream. Monitor CAN bus voltage levels between ECM and HPCU—should show 2.5V (CAN-H) and 2.5V (CAN-L) with differential voltage around 2V during communication. Check termination resistor values (should read approximately 60 ohms across CAN-H and CAN-L). For used machines, perform a wiggle test on harnesses while monitoring live data to identify intermittent connection failures.

Step 3: Component-Level Diagnosis and Repair If electrical checks pass, test the HPCU solenoid output using oscilloscope to verify proper PWM signal generation (typically 12-24V square wave at 100-500 Hz). Compare software versions between ECM and HPCU using diagnostic tool—mismatches require reprogramming with Komatsu factory parameters. On high-hour used excavators, inspect the main grounding points (engine block ground strap and frame ground near battery box) for resistance exceeding 0.5 ohms. Replace degraded harnesses rather than attempting repairs, as splice points create future failure points. If all tests confirm component failure, replace the HPCU with genuine Komatsu parts to ensure protocol compatibility.

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Disclaimer: This guide provides general troubleshooting information for educational purposes. Fault code diagnosis on hydraulic excavators involves high-pressure systems and electrical components requiring specialized training. Always consult Komatsu service documentation and qualified technicians for repairs, especially on used equipment where modification history may be unknown.