What is Komatsu PC200-8M0 Fault Code DWK2KB?

Fault Code DWK2KB on the Komatsu PC200-8M0 excavator indicates a communication error between the Engine Control Module (ECM) and the Machine Controller (MC), specifically related to CAN bus data transmission failure. This code is part of Komatsu's proprietary diagnostic system and signals that critical operational data is not being properly exchanged between the engine management system and the machine's main controller.

This fault is particularly critical for the PC200-8M0 because this model relies on integrated CAN (Controller Area Network) communication to coordinate engine performance, hydraulic output, and operator interface systems. When communication breaks down, the excavator may enter a protective derate mode or experience erratic behavior, compromising both productivity and safety on the jobsite.

Common Symptoms

When fault code DWK2KB is active, operators typically experience:

• Illuminated warning lights on the instrument cluster, specifically the engine malfunction indicator or machine system warning lamp
• Reduced engine power or derate mode activation, limiting maximum RPM and hydraulic flow
• Intermittent loss of monitor display functions, including loss of real-time operating data on the LCD screen
• Erratic hydraulic response or delayed machine functions due to incomplete communication between control systems
• Error messages displayed on the monitor indicating communication failure or system malfunction

Potential Causes

The most common technical causes of fault code DWK2KB on used PC200-8M0 excavators include:

• Damaged or corroded CAN bus wiring harness, particularly at flex points near the engine mount or operator cab where vibration causes wire chafing
• Loose or oxidized connector pins at the ECM or MC connection points, common in machines with 3,000+ operating hours
• Failed termination resistors in the CAN bus network, which are known to degrade over time in harsh environments
• ECM or Machine Controller internal fault, though less common than harness-related issues
• Voltage supply issues to either control module, often caused by corroded ground connections or failing relay circuits
• Aftermarket modifications or previous repair work that compromised the original CAN bus architecture

How to Troubleshoot and Fix Code DWK2KB

Step 1: Visual Inspection and Connection Check Begin by thoroughly inspecting all wiring harnesses between the ECM (located near the engine) and the Machine Controller (typically behind the operator seat). Look for obvious damage, wire chafing, or connector corrosion. On used excavators, pay special attention to harness routing where it passes through the swing bearing area—a known wear point on this model. Disconnect and reconnect all CAN bus connectors, cleaning pins with electrical contact cleaner and checking for bent or pushed-back pins.

Step 2: CAN Bus Electrical Testing Using a digital multimeter, measure the CAN-High and CAN-Low resistance between the two communication wires at the ECM connector (typically pins 26 and 27, but verify with the service manual). You should read approximately 60 ohms with the key off, indicating proper termination resistor function. With the key on, measure voltage levels: CAN-High should read approximately 2.5-3.5V and CAN-Low should read 1.5-2.5V relative to ground. Significant deviation indicates a short, open circuit, or failed termination resistor.

Step 3: Advanced Diagnostics with Komatsu Software Connect Komatsu diagnostic software (KOMTRAX PC application or authorized diagnostic tool) to access detailed communication logs. Check for intermittent errors that may point to a specific module or circuit. If communication is completely absent, perform an ECM and MC power supply check, ensuring each module receives proper 24V input voltage and has clean ground connections. For used machines, remove control modules and inspect connector backs for green oxidation (copper corrosion), which is common in humid environments and causes intermittent faults.

Step 4: Component Replacement and Verification If diagnostics indicate a failed component, replace the damaged harness section, corroded connectors, or faulty control module as identified. After replacement, clear all fault codes and perform a complete machine function test, monitoring for code reoccurrence. On used excavators, consider applying dielectric grease to all repaired connections to prevent future corrosion.

---

Disclaimer: This guide provides general diagnostic information for fault code DWK2KB. Always consult the official Komatsu service manual for your specific machine serial number and consider engaging a certified Komatsu technician for complex electrical diagnostics. Improper troubleshooting of CAN bus systems can cause additional control module damage.