What is Komatsu PC210LC-8 Fault Code DHSAMA?

Fault Code DHSAMA on the Komatsu PC210LC-8 indicates a communication error or data transmission failure within the machine's hydraulic system monitoring network, specifically related to the main pump control signals or pressure sensor feedback loop. This diagnostic trouble code (DTC) typically points to an interruption in the CAN bus communication between the Engine Control Module (ECM) and the Hydraulic System Controller, or a malfunction in one of the critical pressure sensors that regulate pump flow and system performance.

This code is particularly critical for the PC210LC-8 because this model relies on advanced closed-center hydraulic circuits with electronic load-sensing technology. When communication breaks down, the excavator's intelligent hydraulic management system cannot properly adjust pump displacement, leading to inefficient operation, reduced power, and potential damage to hydraulic components. For used excavators, this fault often emerges due to age-related degradation of electrical connections or sensor drift.

Common Symptoms

• Hydraulic system enters limp mode with noticeably reduced swing speed, boom lift capacity, or bucket breakout force
• Intermittent or constant warning light on the instrument cluster, often accompanied by a buzzer or audible alarm
• Erratic engine RPM response when hydraulic functions are engaged, particularly under heavy load conditions
• Machine may start normally but shows degraded performance after 15-30 minutes of operation as components heat up
• Diagnostic monitor displays communication errors or shows dashes/blank readings for hydraulic pressure values

Potential Causes

Electrical Connection Issues are the most common culprits in used PC210LC-8 machines, particularly corrosion or looseness at the main wiring harness connectors located near the hydraulic pump assembly where exposure to hydraulic fluid mist and vibration is constant.

Main Pump Pressure Sensor Failure ranks second, as these sensors deteriorate over 8,000-10,000 operating hours due to constant pressure cycling and contamination from hydraulic fluid breakdown products.

CAN Bus Wiring Damage occurs frequently where harnesses pass through the swing bearing area or along the boom base—known rub points for this model where insulation wears through and causes intermittent short circuits.

ECM or Hydraulic Controller Internal Faults are less common but possible in high-hour machines, particularly if previous electrical issues caused voltage spikes.

Corroded Ground Points near the battery box or pump mounting bracket can create voltage reference problems affecting sensor signal integrity.

How to Troubleshoot and Fix Code DHSAMA

Step 1: Visual Inspection and Connector Verification Begin by thoroughly inspecting all electrical connectors associated with the hydraulic pump assembly and main pressure sensors. On used excavators, pay special attention to the large multi-pin connector at the pump solenoid pack—remove it, check for green corrosion, bent pins, or hydraulic fluid contamination. Clean connections with electrical contact cleaner and apply dielectric grease before reconnection.

Step 2: Sensor Circuit Testing Using a digital multimeter, measure the supply voltage to the main pump pressure sensors (should read 4.8-5.2V DC with ignition on). Check sensor signal output under static conditions—typically 0.5-4.5V depending on system pressure. Compare readings against Komatsu's specification chart in the service manual. For the PC210LC-8, resistance values across sensor terminals should read 250-350 ohms at 20°C.

Step 3: CAN Bus Communication Verification Connect Komatsu diagnostic software (KOMTRAX or PC Service Tool) to check for active communication between controllers. Monitor live data streams while operating hydraulics to identify intermittent signal drops. Check CAN bus termination resistors (should measure 60 ohms between CAN-H and CAN-L wires with power off). Inspect harness routing through the swing bearing and boom pivot areas for chafing.

Step 4: Component Replacement Priority If diagnostics point to a failed sensor, replace the main pump pressure sensor first (Komatsu part number typically 7861-93-1650 or equivalent). For harness damage, repair using proper gauge wire and heat-shrink connections rather than quick splices. If multiple sensors show drift or the ECM cannot establish communication after connector service, the hydraulic controller module may require replacement or reprogramming.

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Disclaimer: This guide provides general troubleshooting information for the Komatsu PC210LC-8 fault code DHSAMA. Hydraulic and electronic systems involve high pressures and voltages. Always consult the manufacturer's official service manual and consider professional diagnostic services, especially for used machines with unknown service history. Improper repairs can result in catastrophic component failure or safety hazards.