Komatsu PC210LC-10 Fault Code DHSDMA: Technical Guide

What is Komatsu PC210LC-10 Fault Code DHSDMA?

Fault code DHSDMA on the Komatsu PC210LC-10 indicates a communication error in the Digital Hydraulic System Data Multiplexing Anomaly—specifically a disruption in the CAN bus network between the hydraulic control ECU and the engine controller.

This diagnostic trouble code (DTC) signals that the multiplexed data exchange between critical control modules has been interrupted or corrupted. The PC210LC-10 relies on seamless communication between its engine ECM and hydraulic controller to optimize fuel efficiency, implement load-sensing hydraulics, and coordinate swing/boom operations. When DHSDMA appears, the excavator may default to backup control modes, significantly reducing operational efficiency and hydraulic response times. This fault is particularly critical on used machines where corrosion and connector degradation compromise the integrity of the CAN network.

Common Symptoms

When fault code DHSDMA is active, operators typically experience:

• Hydraulic system derate – Reduced swing speed and sluggish boom/bucket response, especially under combined operations
• Engine power limitations – ECM may restrict RPM to 1,800 or enter "limp mode" to protect components
• Intermittent warning lamp – Monitor panel displays amber hydraulic system warning, sometimes flashing during certain machine functions
• Erratic attachment response – Auxiliary hydraulics may cut out unexpectedly or fail to activate
• Diagnostic monitor errors – Multiple secondary codes may appear related to hydraulic pressure sensors or swing motor controllers

Potential Causes

The DHSDMA fault code typically stems from these common issues in used PC210LC-10 excavators:

• CAN bus wiring damage – Harness rub points near the swing bearing and along the boom cylinder create shorts or open circuits
• Corroded connector pins – The 38-pin main hydraulic controller connector (located under operator platform) is prone to moisture intrusion on machines over 5,000 hours
• Failed termination resistors – 120-ohm resistors at network endpoints degrade, causing signal reflection and data corruption
• Hydraulic ECU internal failure – Capacitor aging in the control board disrupts digital signal processing
• Engine-to-chassis ground issues – Poor grounding at battery or frame connection points creates voltage reference errors between controllers

How to Troubleshoot and Fix Code DHSDMA

Step 1: Verify Communication Network Integrity Connect Komatsu KOMTRAX diagnostic software or a compatible J1939 scan tool to the diagnostic port beneath the cab. Monitor live data to confirm whether the hydraulic ECU is visible on the network. Check for CAN-High and CAN-Low voltage levels (should read 2.5V at rest, with 1V differential during communication). Inspect all connectors along the main harness—particularly the swing post connector and hydraulic valve bank connector—for green corrosion, bent pins, or moisture.

Step 2: Test CAN Bus Termination and Resistance Disconnect battery power. Using a digital multimeter, measure resistance between CAN-High (typically yellow wire) and CAN-Low (green wire) at the engine ECM connector. You should read approximately 60 ohms (indicating two 120-ohm resistors in parallel at network ends). Readings above 80 ohms or below 50 ohms indicate failed termination resistors or shorted wiring. On used excavators, physically trace the harness from cab to engine bay, checking for abrasion points where the harness contacts the boom cylinder or frame rails.

Step 3: Replace Damaged Components and Clear Codes If wiring checks pass, substitute the hydraulic controller ECU with a known-good unit (calibration transfer required via diagnostic software). Before replacing expensive modules on used machines, clean all connector contacts with electrical contact cleaner and apply dielectric grease to prevent future corrosion. After repairs, clear codes, perform a hydraulic calibration procedure through the service menu, and conduct a full operational test under load.

---

Disclaimer: This guide provides general troubleshooting information for the Komatsu PC210LC-10 DHSDMA fault code. Always consult the manufacturer's service manual and consider professional diagnostic assistance for complex electrical issues. Improper repairs may void warranties or create safety hazards.