Komatsu PC110-8M0 Fault Code DGH2KB: Complete Diagnostic Guide

What is Komatsu PC110-8M0 Fault Code DGH2KB?

Fault Code DGH2KB indicates a communication error between the machine's main Engine Control Module (ECM) and the hydraulic pump control system, specifically related to the load sensing pressure sensor circuit malfunction or data transmission failure.

This code is part of Komatsu's KOMTRAX-integrated diagnostic system used in the Dash-8M0 series excavators. The PC110-8M0 utilizes a sophisticated closed-loop hydraulic system that relies on constant communication between the engine controller and hydraulic controller to optimize fuel efficiency and hydraulic performance. When the ECM cannot receive valid pressure data from the load sensing circuit, it triggers DGH2KB to prevent potential damage from operating with incorrect hydraulic pressure calculations. This is particularly critical because the pump displacement is controlled electronically based on this sensor feedback.

Common Symptoms

When fault code DGH2KB is active on your Komatsu PC110-8M0, operators typically experience:

• Hydraulic system power reduction or noticeably sluggish boom/arm movements, especially under load
• Amber warning light illuminated on the instrument cluster with possible fault code display
• Intermittent loss of fine control during precise digging operations due to inconsistent pressure regulation
• Engine RPM fluctuations when engaging hydraulics, as the ECM cannot properly match engine output to hydraulic demand
• Increased fuel consumption as the system defaults to a conservative failsafe mapping

Potential Causes

The most common technical failures triggering DGH2KB on used PC110-8M0 excavators include:

• Load sensing pressure sensor failure (located on the main hydraulic pump) – internal sensor element degradation is common after 4,000+ operating hours
• Corroded or moisture-damaged connector at the pressure sensor – the C-237 connector is particularly vulnerable on machines operating in wet conditions
• Wiring harness chafing where the sensor cable routes near the swing motor mount – a known wear point on this model
• ECM internal fault affecting the analog-to-digital converter circuit for pressure sensor input
• Poor ground connection at G-104 ground point on the pump mounting bracket
• Software corruption in hydraulic controller requiring ECM reprogramming with Komatsu's KTEC diagnostic software

How to Troubleshoot and Fix Code DGH2KB

Step 1: Visual Inspection and Connector Check Begin by accessing the main hydraulic pump (located left side of engine). Inspect the load sensing pressure sensor and its associated three-pin connector (C-237). On used excavators, check carefully for corrosion, bent pins, or moisture intrusion. Clean contacts with electrical contact cleaner and apply dielectric grease. Examine the entire wiring harness from sensor to ECM for abrasion damage, particularly where it passes the swing motor mounting area.

Step 2: Electrical Circuit Testing Using a digital multimeter (DMM), perform resistance checks on the sensor circuit. With the ignition OFF and connector disconnected at the sensor, measure resistance between sensor pins 1 and 2 – you should see approximately 240-360 ohms at 20°C. Check continuity from sensor connector to ECM connector (C-14, pins 23, 24, and ground) – resistance should be less than 5 ohms per wire. Any reading above this indicates damaged wiring requiring harness repair or replacement.

Step 3: Sensor Power and Signal Verification Reconnect the sensor and backprobe the connector with ignition ON, engine OFF. Verify 5-volt reference supply from ECM on pin 1 (typically red wire). Ground should show 0 volts on pin 3 (black wire). The signal wire (pin 2, typically white/blue) should read approximately 0.5-4.5 volts depending on system pressure. If voltage is absent or outside parameters, suspect ECM internal fault.

Step 4: Sensor Replacement and Calibration If electrical tests pass but code persists, replace the load sensing pressure sensor (Komatsu Part #7861-93-1650). On used machines, always replace the O-ring seal and torque to 15-20 Nm. After replacement, use Komatsu KTEC software to perform sensor calibration procedure and verify proper data reception at the ECM.

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Disclaimer: This guide provides general diagnostic information for reference purposes. Always consult the official Komatsu PC110-8M0 service manual and consider engaging a certified Komatsu technician for complex electrical diagnostics. Improper repairs may cause additional system damage or safety hazards.