What is Komatsu PC210LC-8M0 Fault Code DHSDMA?

Fault Code DHSDMA on the Komatsu PC210LC-8M0 excavator indicates a communication error or malfunction within the hydraulic system's electronic control circuit, specifically related to the hydraulic pump delivery control or swing system data transmission. This diagnostic trouble code (DTC) is generated when the machine's Controller Area Network (CAN) detects abnormal signal communication between the engine ECM (Engine Control Module) and the pump controller or hydraulic sensors.

This fault is critical for the PC210LC-8M0 because it directly affects the machine's ability to optimize hydraulic flow and pressure based on operational demands. When communication breaks down, the excavator may default to limp mode, restricting productivity and potentially causing accelerated wear on hydraulic components due to improper pressure regulation. For used excavators, this code often surfaces due to aging wiring harnesses or corroded connector pins that deteriorate over years of exposure to moisture and vibration.

Common Symptoms

• Hydraulic system derate: Reduced swing speed, sluggish boom/arm movements, or inconsistent bucket control
• Warning indicators: Amber or red hydraulic system warning light illuminated on the monitor panel
• Error messages: Display shows communication errors or system malfunction alerts
• Intermittent performance issues: Machine operates normally at startup but develops problems after warming up, indicating heat-related connection failures
• Fuel efficiency drop: Engine runs at higher RPMs to compensate for improper hydraulic load sensing

Potential Causes

• Corroded or loose connectors on the hydraulic pump controller harness (extremely common in machines with 5,000+ hours)
• Damaged CAN bus wiring: Chafing at known rub points near the swing bearing or along the boom base where harnesses flex repeatedly
• Failed pump solenoid valve or pressure sensor: Internal electrical faults preventing proper signal transmission
• ECM or pump controller internal fault: Rare but possible in high-hour used machines with software corruption
• Voltage supply issues: Low battery voltage or poor grounding at the pump controller due to corroded ground straps
• Water ingress: Moisture infiltration in connector housings, particularly in machines operated in wet environments

How to Troubleshoot and Fix Code DHSDMA

Step 1: Visual Inspection and Connection Check
Begin by inspecting all wiring harnesses connected to the hydraulic pump controller and pressure sensors. Pay special attention to areas where harnesses contact the frame or pass through the swing bearing. Look for abraded insulation, crushed wires, or green corrosion on connector pins. Clean all connectors with electrical contact cleaner and apply dielectric grease to prevent future corrosion—a critical step for used excavators.

Step 2: Diagnostic Software Analysis
Connect Komatsu KOMTRAX or a compatible diagnostic tool (such as a Komatsu PC diagnostic interface) to read live data streams. Monitor the CAN bus communication status between the ECM and pump controller. Check for voltage irregularities: the pump solenoid should receive approximately 12-24V (verify exact specifications in the service manual). If communication is intermittent, gently wiggle harness connectors while monitoring—this often reveals loose terminals.

Step 3: Component Testing and Voltage Verification
Using a digital multimeter (DMM), test the pump pressure sensors for proper resistance values (typically 200-500 ohms, consult factory specs). Verify ground continuity from the pump controller to the battery negative terminal—resistance should be less than 1 ohm. Check CAN bus termination resistance (should read approximately 60 ohms between CAN-High and CAN-Low lines). For used excavators, also inspect the swing bearing electrical slip ring for wear, as this can interrupt communication signals.

Step 4: Replacement and Recalibration
If diagnostics indicate a failed component, replace the pump controller solenoid, pressure sensor, or damaged harness section with genuine Komatsu parts. After replacement, clear the fault code using diagnostic software and perform a pump calibration procedure following the service manual's specific steps for the PC210LC-8M0. Test the machine under normal working loads for at least 30 minutes to confirm the repair.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu service manual for your specific machine serial number and follow proper safety lockout/tagout procedures. If unfamiliar with hydraulic or electrical systems, seek assistance from a certified Komatsu dealer or qualified heavy equipment technician. Improper diagnosis can lead to equipment damage or personal injury.