Komatsu PC210-10 Fault Code DHSAMA: Complete Diagnostic Guide

What is Komatsu PC210-10 Fault Code DHSAMA?

Fault Code DHSAMA indicates a hydraulic system abnormality related to the Demand Hydraulic System Automatic Mode Adjustment malfunction. This code specifically triggers when the ECM (Engine Control Module) detects an inconsistency between the commanded hydraulic pump flow and the actual system response in automatic working mode.

The DHSAMA fault directly affects the PC210-10's advanced hydraulic matching system, which automatically optimizes pump output based on engine load and operator demand. This intelligent system is critical for fuel efficiency and excavator performance, as it regulates the variable displacement pumps to prevent engine lugging while maintaining digging force. When this code activates, the machine typically defaults to a conservative hydraulic mode, significantly reducing productivity and increasing fuel consumption.

Common Symptoms

• Automatic mode failure – excavator cannot enter or maintain Auto/Economy working modes
• Reduced hydraulic power across all functions (boom, arm, bucket, and swing)
• Engine RPM fluctuations under load, particularly during combined hydraulic operations
• Monitor warning light illuminated with possible "Check Hydraulic System" message
• Noticeably slower cycle times compared to normal operation, especially in digging applications

Potential Causes

The DHSAMA code on used PC210-10 excavators typically stems from these technical failures:

• Pressure sensor degradation – the main pump pressure sensor (located on pump regulator) develops internal resistance issues after 5,000+ operating hours
• Solenoid valve contamination – proportional control solenoids for pump displacement stick due to hydraulic oil degradation or particle contamination
• Wiring harness damage – connector corrosion or wire chafing at known rubbing points near the pump assembly and along the right-side main frame
• ECM calibration drift – software corruption or memory errors in older control modules
• Hydraulic oil quality issues – incorrect viscosity or contaminated oil affecting sensor accuracy

How to Troubleshoot and Fix Code DHSAMA

Step 1: Connect Diagnostic Software Use Komatsu KOMTRAX or PC Service Tool to retrieve freeze frame data. Document engine RPM, hydraulic temperature, and pump pressure readings when the fault occurred. This establishes baseline conditions for diagnosis.

Step 2: Inspect Pressure Sensors and Wiring Locate the main pump pressure sensor on the regulator assembly. Check connector pins for corrosion (common on used machines). Using a digital multimeter, verify sensor output voltage (should range 0.5-4.5V depending on pressure). Inspect the entire sensor harness from pump to ECM, paying special attention to routing near the swing motor where abrasion frequently occurs.

Step 3: Test Solenoid Valve Operation Access the pump control solenoid valves and measure resistance (typically 20-30 ohms). Use diagnostic software to command solenoid actuation while monitoring current draw. Remove and inspect valves for varnish buildup or metal particles—critical on excavators with questionable maintenance history.

Step 4: Verify Hydraulic Oil Condition Sample the hydraulic tank and check for contamination, water content, and viscosity. On used excavators, degraded oil significantly impacts sensor accuracy and valve response. Replace filters and oil if contamination is present before condemning components.

Step 5: Perform ECM Reset and Calibration After physical repairs, clear fault codes and perform pump calibration procedure through service software. Run the excavator through full hydraulic functions and monitor real-time data to confirm proper automatic mode engagement.

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Disclaimer: This guide provides general troubleshooting information. Always consult qualified Komatsu technicians and refer to the official PC210-10 service manual for model-specific procedures. Hydraulic system work requires proper safety precautions and specialized tools.