Komatsu PC210LC-8 Fault Code DHS3MA: Diagnostic Guide

What is Komatsu PC210LC-8 Fault Code DHS3MA?

Fault code DHS3MA indicates a hydraulic system communication error between the machine's ECM (Engine Control Module) and the hydraulic pump control system, specifically related to the main pump delivery pressure sensor circuit malfunction.

This code signifies that the ECM is receiving abnormal voltage signals from the pump delivery pressure sensor, which monitors the hydraulic system's main circuit pressure. On the Komatsu PC210LC-8, this sensor is critical for the machine's load-sensing hydraulic system, which automatically adjusts pump output based on operational demand. When this communication fails, the excavator cannot properly regulate hydraulic flow, directly impacting digging force, swing speed, and fuel efficiency. This is particularly problematic in used machines where sensor degradation affects the advanced CLSS (Closed Center Load Sensing System) that defines this model's performance.

Common Symptoms

When DHS3MA is active on your PC210LC-8, operators typically experience:

• Hydraulic system derate – noticeably reduced digging force and slower cylinder movements across all functions
• Amber warning light illuminated on the monitor panel with accompanying fault code display
• Erratic hydraulic response – inconsistent boom or arm speed during combined operations
• Increased fuel consumption due to the pump running at maximum displacement instead of load-matching
• Intermittent loss of hydraulic power during high-demand operations like deep trenching or lifting

Potential Causes

The DHS3MA code on used PC210LC-8 excavators typically stems from:

• Pressure sensor failure – internal sensor element degradation (common after 8,000+ operating hours)
• Corroded or damaged connector pins at the sensor harness connection point near the main pump assembly
• Wiring harness chafing where the sensor cable routes along the pump mounting bracket (known wear point on this model)
• ECM communication fault due to voltage irregularities or poor grounding at the controller
• Contaminated hydraulic oil causing sensor membrane fouling or mechanical damage
• Water intrusion into the sensor connector (especially on machines with compromised cab seals)

How to Troubleshoot and Fix Code DHS3MA

Step 1: Visual Inspection Begin by locating the main pump delivery pressure sensor on the right-side main pump (when facing forward from the cab). Inspect the sensor body and wiring harness for physical damage, oil contamination, or visible corrosion. On used excavators, pay special attention to where the harness contacts the pump mounting bracket – this is a common abrasion point causing intermittent shorts.

Step 2: Electrical Testing Disconnect the sensor's electrical connector and inspect pins for corrosion or bent contacts. Using a digital multimeter, check sensor resistance (should read 250-350 ohms at room temperature per Komatsu specifications). Then verify supply voltage at the harness connector with ignition on – you should measure approximately 5 volts DC on the signal wire. If voltage is absent or incorrect, trace wiring back to the ECM checking for opens or shorts.

Step 3: Signal Output Verification Reconnect the sensor and use Komatsu KOMTRAX diagnostic software or a compatible scan tool to monitor live pressure sensor data while operating hydraulics. The reading should fluctuate between 0-350 bar depending on load. Static readings or values pegged at maximum indicate sensor failure. For used machines, remove and clean the sensor port threads and install a new O-ring seal even if replacing the sensor – old seal degradation causes pressure leaks affecting readings.

Step 4: System Pressure Test If electrical tests pass, perform a physical hydraulic pressure test using a calibrated gauge at the test port near the main control valve. Compare actual pressure to sensor readings. A discrepancy exceeding 10% confirms sensor inaccuracy requiring replacement. Always use genuine Komatsu pressure sensors (Part #7861-93-1650) as aftermarket sensors frequently cause repeat codes.

Disclaimer: This guide provides general diagnostic information. Hydraulic system repairs involve high-pressure components and specialized tools. Always consult qualified Komatsu technicians and refer to the official PC210LC-8 service manual for complete procedures and safety precautions before performing repairs on used excavators.