What is Komatsu PC110-8M0 Fault Code DWK0KA?

Fault code DWK0KA on the Komatsu PC110-8M0 excavator indicates a communication error between the engine Electronic Control Module (ECM) and the hydraulic system controller. This diagnostic trouble code (DTC) specifically points to a CAN bus communication failure affecting data transmission between critical control systems.

The Komatsu PC110-8M0 relies on constant communication between its engine management system and hydraulic controller to optimize performance, fuel efficiency, and emissions control. When code DWK0KA triggers, it means the ECM cannot properly communicate with downstream controllers, potentially affecting engine derate logic, hydraulic response timing, and overall machine coordination. This is particularly critical on the PC110-8M0 platform, which uses integrated control systems to balance power output with hydraulic demand during simultaneous operations.

Common Symptoms

When fault code DWK0KA is active, operators typically experience:

• Warning lamp illumination on the instrument cluster, often accompanied by a wrench or diagnostic icon
• Reduced hydraulic response or sluggish boom/arm movements due to impaired system coordination
• Engine power derate (limp mode) that limits RPM to protect components when sensor data is unavailable
• Intermittent control issues where machine performance fluctuates unpredictably during operation
• Error messages displayed on the monitor panel indicating communication faults between controllers

Potential Causes

The most common technical reasons for DWK0KA fault code on used PC110-8M0 excavators include:

• Damaged CAN bus wiring harness between ECM and hydraulic controller, especially at known rub points near the swing bearing or along the boom base
• Corroded or loose electrical connectors on the controller area network (CAN) circuit due to water intrusion or age-related degradation
• Failed termination resistors on the CAN bus network (typically 120-ohm resistors at each network end)
• ECM or hydraulic controller internal failure causing inability to send/receive data packets properly
• Low system voltage from weak batteries or failing alternators disrupting controller communication protocols
• Aftermarket component interference from improperly installed accessories that create electrical noise on the CAN network

How to Troubleshoot and Fix Code DWK0KA

Step 1: Visual Inspection and Connection Check Begin by inspecting the wiring harness between the engine ECM (located behind the operator cab) and the hydraulic controller (typically mounted near the hydraulic pump). On used excavators, pay special attention to harness routing through the swing bearing area and boom pivot points where cable flexing causes insulation wear. Check all CAN bus connectors (often green-colored on Komatsu systems) for corrosion, pushed-back pins, or moisture intrusion. Clean contacts with electrical contact cleaner and apply dielectric grease before reconnecting.

Step 2: CAN Bus Resistance Testing Using a digital multimeter (DMM), measure resistance across the CAN-High and CAN-Low wires at the ECM connector with the ignition off and connectors separated. You should read approximately 60 ohms (two 120-ohm termination resistors in parallel). Readings significantly higher suggest an open circuit in the harness or failed termination resistor. Check resistance between each CAN wire and ground—readings below 10k ohms indicate a short to ground. For used machines, physically trace and inspect harnesses for chafe marks where cables contact metal edges.

Step 3: Voltage and Signal Quality Check With the ignition on, back-probe the CAN-High and CAN-Low terminals at the hydraulic controller using a DMM or oscilloscope. You should measure approximately 2.5V DC on each line when idle. During active communication, an oscilloscope should show clean differential voltage pulses without excessive noise. If using Komatsu KOMTRAX diagnostic software or an aftermarket tool compatible with J1939 protocol, monitor live CAN bus traffic to identify missing messages from specific controllers.

Step 4: Controller and Component Testing If wiring and signals test correctly, the fault likely resides in a controller. Swap the hydraulic controller with a known-good unit if available, or test the ECM by checking for updated software versions. On higher-hour used excavators, ECM capacitor degradation is common—look for bulging capacitors through the ECM casing inspection ports if accessible. Verify battery voltage remains above 12.5V during cranking, as voltage sags can cause communication dropouts that set intermittent codes.

Disclaimer: This guide provides general troubleshooting information for educational purposes. Always consult the official Komatsu service manual for your specific machine serial number, and consider having a certified Komatsu technician diagnose complex electrical issues. Improper diagnostic procedures can cause additional damage to sensitive electronic components.