What is Komatsu PC210-8 Fault Code DW43KA?

Fault code DW43KA on the Komatsu PC210-8 excavator indicates a communication error between the Engine Control Module (ECM) and the Hydraulic Pump Control (HPC) system. This diagnostic trouble code specifically signals that the ECM has detected an abnormal signal or loss of data transmission from the hydraulic pump controller, which manages the machine's variable displacement pumps and overall hydraulic performance.

This fault is critical for the PC210-8 because the ECM and HPC must constantly communicate to optimize fuel efficiency, engine load, and hydraulic flow based on real-time operating conditions. When this communication fails, the excavator's intelligent Machine Control system cannot properly coordinate engine speed with hydraulic demand, potentially causing reduced productivity and increased fuel consumption. On used machines, this code often appears due to age-related electrical degradation rather than catastrophic component failure.

Common Symptoms

• Machine derate mode: Engine power limited to approximately 70-80% of normal output with reduced hydraulic response
• Intermittent warning lamp: The hydraulic system warning light flashes or remains illuminated on the instrument cluster
• Sluggish hydraulic operation: Noticeably slower boom, arm, or bucket movements, especially under load
• Engine RPM fluctuation: Unstable idle or surging during operation as the ECM attempts to compensate for missing hydraulic load data
• Error code persistence: Code may intermittently appear and disappear, particularly on cold starts or during temperature changes

Potential Causes

The most common technical causes for DW43KA on used PC210-8 excavators include:

• Corroded or loose connector pins at the X41 or X42 harness connections between the ECM and HPC controller (located near the hydraulic pump assembly)
• CAN bus communication wire damage from harness chafing against the engine block or pump housing—a known wear point on machines with 4,000+ operating hours
• Faulty hydraulic pump controller module experiencing internal circuit degradation (less common but possible on high-hour machines)
• Voltage supply issues to the HPC, typically caused by corroded ground points G301 or G302 on the chassis
• Water intrusion into the ECM or HPC connectors from damaged harness seals or cab floor leaks

How to Troubleshoot and Fix Code DW43KA

Step 1: Inspect Physical Connections Begin by locating the HPC controller mounted on the left side of the hydraulic pump assembly. Disconnect connectors X41 and X42, then carefully inspect all pins for corrosion, bent contacts, or moisture. On used excavators, apply dielectric grease to all pins during reassembly to prevent future corrosion. Check the harness routing for any signs of wear against metal surfaces.

Step 2: Verify CAN Bus Communication Lines Using a digital multimeter, measure resistance between CAN-H and CAN-L wires at the HPC connector. You should read approximately 60 ohms with all other controllers connected (proper termination resistance). Use Komatsu KOMTRAX or PC-based diagnostic software to monitor real-time communication packets between the ECM and HPC—intermittent dropouts indicate harness issues.

Step 3: Check Power Supply and Grounds Verify the HPC receives stable 24V DC supply voltage (key-on, engine-off). Measure voltage drop across ground circuits—readings above 0.2V indicate poor ground connections. For used machines, remove, clean, and reinstall chassis ground points G301 and G302 with fresh star washers.

Step 4: Test HPC Controller Function If harness and power supply checks pass, the hydraulic pump controller itself may require replacement. Before ordering new parts for used equipment, consider testing with a known-good controller from another PC210-8 if available, as genuine Komatsu HPC units cost $800-1,200.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and consider professional diagnosis for complex electrical issues. Improper repairs may cause additional system damage or safety hazards.