Komatsu PC200-10 Fault Code DA2QKR: Complete Diagnostic Guide

What is Komatsu PC200-10 Fault Code DA2QKR?

Fault Code DA2QKR indicates a communication error between the Engine Controller (ECM) and the Hydraulic Pressure Sensor Circuit in Komatsu's KOMTRAX telematics system. This code specifically signals that the ECM has detected an abnormal voltage signal or complete loss of communication from the main hydraulic system pressure sensor, which monitors implement and swing circuit pressures.

This fault is critical for the PC200-10 because this excavator's CLSS (Closed-Center Load Sensing System) relies on precise hydraulic pressure feedback to optimize fuel efficiency and performance. When the ECM cannot accurately read hydraulic pressure data, the machine may enter a protective derate mode, limiting pump output to prevent potential damage to the hydraulic system.

Common Symptoms

When DA2QKR is active on your PC200-10, operators typically experience:

• Yellow warning light illuminated on the instrument cluster with reduced hydraulic power
• Sluggish boom, arm, or bucket response, particularly under load conditions
• Engine RPM fluctuations during simultaneous multi-function operations
• KOMTRAX system alerts sent to fleet management systems or operator displays
• Reduced swing speed and overall cycle times during digging operations

Potential Causes

The most common technical causes for DA2QKR on used PC200-10 excavators include:

• Hydraulic pressure sensor failure (Komatsu P/N 7861-93-1650) due to internal diaphragm rupture or contamination
• Damaged wiring harness between the sensor and ECM, especially at known rub points near the main pump mounting area
• Corroded or loose connector pins at the 12-pin sensor connector (C204), common on machines with 5,000+ operating hours
• ECM voltage supply issues providing incorrect 5V reference voltage to the sensor circuit
• Contaminated hydraulic oil causing sensor membrane fouling or false readings

How to Troubleshoot and Fix Code DA2QKR

Step 1: Initial Inspection Connect Komatsu KDPF (Komatsu Diagnostic Program for Field) diagnostic software or an OEM-compatible scan tool. Record active and stored codes, then inspect the hydraulic pressure sensor located on the main control valve manifold (left side of pump). Check for physical damage, oil leaks around the sensor body, or loose mounting.

Step 2: Electrical Testing Disconnect the sensor connector C204 and inspect pins for corrosion, bent terminals, or oil contamination—critical on used excavators. Using a digital multimeter, measure the 5V reference voltage from the ECM at pins 1 and 3 (key ON, engine OFF). Verify ground continuity (less than 1 ohm resistance) on pin 2. Check sensor resistance across pins 1 and 3; specification is typically 250-350 ohms at room temperature.

Step 3: Harness and Sensor Replacement Trace the sensor harness from C204 to the ECM connector, checking for abrasion at known wear points: alongside the hydraulic tank, near rotating joints, and through bulkhead grommets. Replace damaged sections with OEM-spec shielded wire. If electrical tests pass but the code persists, replace the hydraulic pressure sensor with a genuine Komatsu component and calibrate using KDPF software.

Step 4: System Verification Clear codes, operate the machine through full hydraulic cycles (boom raise/lower, swing left/right, bucket curl), and monitor live data. Verify pressure readings range from 0-350 bar (0-5,075 PSI) under load conditions.

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Disclaimer: This guide provides general troubleshooting information. Always consult Komatsu's official service manual for your specific machine serial number and hydraulic system configuration. If unfamiliar with high-pressure hydraulic systems or electrical diagnostics, contact a certified Komatsu technician to prevent injury or equipment damage.