What is Komatsu PC110-8M0 Fault Code DW43KA?

Fault Code DW43KA on the Komatsu PC110-8M0 indicates a malfunction in the machine monitoring system's display communication circuit, specifically a data transmission error between the Engine Control Module (ECM) and the monitor panel. This code triggers when the ECM detects abnormal or interrupted communication with the machine's instrument cluster, preventing critical operating data from being displayed to the operator.

This fault is particularly significant for the PC110-8M0 because this mid-size excavator relies on continuous data exchange between multiple controllers to optimize hydraulic performance, fuel efficiency, and emission controls. When communication breaks down, the operator loses visibility into vital engine parameters including coolant temperature, hydraulic oil temperature, fuel levels, and active system warnings. In used excavators, this code often points to age-related deterioration in the CAN bus wiring harness or corroded connectors rather than actual ECM failure.

Common Symptoms

• Monitor panel displays error messages or goes completely blank while the engine continues running
• Warning lights illuminate intermittently or remain constantly on without corresponding system faults
• Loss of gauge functionality including hour meter, fuel gauge, temperature readings, or RPM display
• Intermittent dashboard flickering especially during machine vibration or when operating on uneven terrain
• Engine may enter derate mode or limit power output as a protective measure due to inability to monitor operating conditions

Potential Causes

The DW43KA code typically results from physical deterioration common in used heavy equipment. Corroded or loose connector pins at the monitor panel or ECM connection points rank as the most frequent cause, especially in machines exposed to moisture or operated in coastal/high-humidity environments.

Damaged CAN bus wiring harness represents another prevalent issue in the PC110-8M0. The communication wires running from the ECM to the cab area pass through several articulation points where repeated flexing causes internal wire fractures or insulation wear, creating intermittent connections.

Faulty monitor panel itself can generate this code, particularly in excavators with 3,000+ operating hours where display backlighting components or internal circuit boards deteriorate. ECM internal failure is less common but possible, especially if the machine experienced electrical surges or water intrusion events.

How to Troubleshoot and Fix Code DW43KA

Step 1: Visual Inspection of Connections Begin by disconnecting the battery negative terminal. Locate the monitor panel connector behind the dashboard and the ECM connector in the engine compartment (typically mounted near the battery box on the PC110-8M0). Inspect all pins for green corrosion, bent contacts, or moisture infiltration. Clean connectors using electrical contact cleaner and a wire brush designed for pin terminals. Check connector seals for cracking or compression damage.

Step 2: CAN Bus Harness Continuity Testing Using a digital multimeter, test continuity between the monitor panel connector and ECM connector on the CAN-H and CAN-L communication wires (refer to Komatsu wiring diagram for specific pin locations, typically yellow and green wires). Resistance should read under 5 ohms. Wiggle the harness while testing to reveal intermittent breaks. Pay special attention to harness routing near the swing post and any cable tie points where friction may have worn through insulation.

Step 3: Resistance Check and Termination Verification The CAN bus network requires proper termination resistance between CAN-H and CAN-L. With all controllers connected and key off, measure resistance between these two wires—it should read approximately 60 ohms (two 120-ohm terminating resistors in parallel). Readings significantly higher suggest open termination or harness damage.

Step 4: Monitor Panel Power Supply Verification Verify the monitor panel receives proper 12-24V DC power supply and clean ground connection. Voltage drop testing on the ground circuit should show less than 0.5V. In used excavators, ground connection deterioration at chassis mounting points frequently causes communication errors.

Step 5: Component Substitution Testing If harness and connections test properly, substitute with a known-good monitor panel to isolate whether the display unit has failed. ECM replacement should be the last resort after eliminating all wiring and connector issues, as this represents the most expensive repair.

Critical for Used Excavators: Before ordering replacement parts, thoroughly inspect all wire harness mounting brackets and protective conduit for damage. Aftermarket repairs or modifications may have rerouted wiring improperly, creating new rub points.

---

Disclaimer: This guide provides general troubleshooting information for the Komatsu PC110-8M0. Always consult the manufacturer's service manual for model-specific procedures, torque specifications, and safety protocols. Complex electrical diagnostics may require Komatsu diagnostic software (KOMTRAX) and should be performed by certified technicians when warranty or liability concerns exist.