What is Komatsu PC240LC-8 Fault Code DA25KP?

Fault Code DA25KP indicates a malfunction in the hydraulic pump delivery pressure sensor circuit or an abnormal pressure reading detected by the Engine Control Module (ECM). This code is specific to Komatsu's KOMTRAX monitoring system and signals that the ECM has detected either an electrical fault in the sensor wiring or a hydraulic pressure reading outside the normal operating parameters for the PC240LC-8's main pump system.

This fault is critical because the hydraulic pump delivery pressure sensor provides real-time feedback to the ECM, enabling precise control of engine output to match hydraulic load demands. When this sensor circuit fails, the machine cannot properly optimize fuel efficiency, and the hydraulic system may experience performance degradation. On the PC240LC-8, this sensor directly affects the engine-pump matching system, which is essential for coordinated power delivery during heavy excavation work.

Common Symptoms

When fault code DA25KP is active, operators typically experience:

• Illuminated warning light on the instrument cluster, often accompanied by a wrench or diagnostic icon
• Reduced hydraulic performance, particularly noticeable during combined operations (swing + boom + bucket functions)
• Engine derating or automatic power reduction mode, limiting machine to approximately 80% of normal output
• Erratic engine response to hydraulic load changes, with possible hunting or surging at idle
• KOMTRAX system alerts sent to fleet managers if telematics are active

Potential Causes

The most common technical reasons for DA25KP appearing on used PC240LC-8 excavators include:

• Damaged or corroded sensor connector at the hydraulic pump—this location is exposed to hydraulic oil mist and debris
• Worn wiring harness where it runs along the pump mounting bracket, a known rub point on machines with 4,000+ operating hours
• Failed pressure sensor (Komatsu part number typically 7861-93-1650 or equivalent), common after 6,000-8,000 hours
• Intermittent short to ground in the sensor signal wire due to insulation breakdown
• ECM software glitch requiring calibration update, particularly on early production 2008-2010 models
• Actual hydraulic pressure abnormality caused by worn pump components or contaminated hydraulic oil

How to Troubleshoot and Fix Code DA25KP

Step 1: Visual Inspection and Connection Check Begin by locating the hydraulic pump delivery pressure sensor on the main pump assembly (driver's side of engine). Disconnect the three-pin connector and inspect for oil contamination, corroded pins, or damaged seals. Clean with electrical contact cleaner and check the rubber seal integrity. On used excavators, this connector frequently shows green corrosion on pin terminals.

Step 2: Electrical Testing Using a digital multimeter, perform resistance and voltage checks. With ignition on (engine off), measure reference voltage at the ECM side of the harness—you should see approximately 5 volts on the signal wire. Check sensor resistance (sensor disconnected) which should read 250-350 ohms at 20°C. Inspect the ground circuit for continuity; resistance to chassis ground should be less than 1 ohm.

Step 3: Harness Inspection and Sensor Replacement Trace the wiring harness from sensor to ECM, paying special attention to the flex point near the pump mounting bracket where abrasion commonly occurs. Look for insulation wear or exposed copper. If electrical tests pass but the code persists, replace the pressure sensor. After replacement on used machines, perform an ECM calibration reset using Komatsu KDPF diagnostic software to clear adaptive learning values.

Step 4: Verify Hydraulic System Function If the code returns after sensor replacement, investigate actual hydraulic issues. Check hydraulic oil condition (contamination can damage sensors), verify main relief valve setting (should be 34.3 MPa/4,975 PSI), and consider pump wear as a root cause in high-hour machines.

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Disclaimer: This guide provides general diagnostic information for experienced technicians. Always consult the official Komatsu PC240LC-8 Service Manual and follow manufacturer-specific procedures. If you lack proper diagnostic tools or training, contact a certified Komatsu dealer or qualified heavy equipment mechanic to prevent further damage to electrical systems.