What is Komatsu PC110-8M0 Fault Code DHSFMA?

Fault Code DHSFMA on the Komatsu PC110-8M0 excavator indicates a communication error or data malfunction within the machine's hydraulic system control network. This code typically signals that the Electronic Control Module (ECM) is not receiving proper data from one or more hydraulic system sensors or controllers, affecting the machine's ability to regulate hydraulic flow, pressure, or temperature accurately.

In the PC110-8M0 model, the hydraulic control system relies on continuous data exchange between multiple sensors—including main pump pressure sensors, pilot pressure sensors, and the hydraulic oil temperature sensor—and the main ECM. When this communication breaks down, the excavator may enter a protective derate mode to prevent catastrophic damage to hydraulic components. For operators of used excavators, this fault is particularly critical because degraded wiring harnesses and corroded connectors are common culprits that can trigger false fault codes or intermittent communication failures.

Common Symptoms

When fault code DHSFMA is active on your Komatsu PC110-8M0, you may experience:

• Warning light illumination on the instrument cluster, often accompanied by a diagnostic trouble code display
• Reduced hydraulic responsiveness or sluggish boom, arm, and bucket movements
• Engine power derate, limiting RPM to protect the hydraulic system from operating outside safe parameters
• Intermittent loss of auxiliary hydraulic functions, such as attachments or thumb controls
• Hydraulic oil temperature warning, even when fluid temperatures appear normal during manual checks

Potential Causes

The following technical issues are most frequently responsible for triggering DHSFMA on used PC110-8M0 excavators:

• Damaged or corroded wiring harness connections between the ECM and hydraulic sensors, especially at known rub points near the swing bearing and along the boom
• Faulty hydraulic system sensors, particularly the main pump pressure sensor or pilot pressure sensor, which commonly fail due to vibration and age
• ECM software glitches or outdated firmware requiring reprogramming with Komatsu's KOMTRAX or diagnostic software
• Corroded ground connections in the cab floor area or engine compartment, disrupting the CAN bus communication network
• Hydraulic oil contamination causing sensor fouling or erratic readings that confuse the control system
• Aftermarket sensor replacements with incorrect specifications or poor quality that don't communicate properly with OEM systems

How to Troubleshoot and Fix Code DHSFMA

Step 1: Connect Diagnostic Software Use Komatsu diagnostic software or a compatible CAN bus scanner to read active and pending fault codes. Record all related codes, as DHSFMA may appear alongside other hydraulic or electrical faults. This provides critical context for pinpointing the root cause, especially on used machines with multiple aged components.

Step 2: Inspect Wiring Harnesses and Connectors Physically inspect all harness routing from the ECM (located under the operator's seat) to each hydraulic sensor. Pay special attention to areas where harnesses pass through the swing bearing, along the boom base, and near the hydraulic pump. Look for chafing, exposed wires, corroded pins, or loose connectors. On used excavators, these wear points are the most common failure sites. Clean all connector pins with electrical contact cleaner and apply dielectric grease to prevent future corrosion.

Step 3: Test Sensor Outputs and Resistance Using a digital multimeter, measure the resistance and voltage output of the main pump pressure sensor and pilot pressure sensor according to Komatsu specifications (typically 0.5-4.5V output range under normal operating conditions). Compare readings against the service manual values. If sensors read open circuit, shorted, or outside specified ranges, replacement is necessary. Always use OEM Komatsu sensors on used machines to ensure proper CAN bus communication.

Step 4: Check Ground Connections and CAN Bus Integrity Verify that all ECM ground points have less than 0.1 ohms resistance to chassis ground. Poor grounds are especially common on older equipment. Inspect the CAN bus termination resistors and verify proper 120-ohm resistance across the network when measured at the ECM connector.

Step 5: Clear Codes and Test Operation After repairs, clear all fault codes using diagnostic software, then operate the machine through full hydraulic cycles under load. Monitor for code reoccurrence. If DHSFMA returns, ECM reprogramming or replacement may be required, particularly if the machine has outdated firmware.

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Disclaimer: This guide provides general troubleshooting information for Komatsu PC110-8M0 excavators. Always consult the official Komatsu service manual and consider professional diagnostic services from certified technicians, especially when working with complex electronic control systems on used heavy equipment.