Komatsu PC200LC-8M0 Fault Code DAZQKR: Diagnostic Guide

What is Komatsu PC200LC-8M0 Fault Code DAZQKR?

Fault Code DAZQKR indicates a communication error between the engine ECM (Engine Control Module) and the hydraulic control system on the Komatsu PC200LC-8M0 excavator. This code specifically relates to a CAN bus (Controller Area Network) communication failure affecting the machine's ability to properly coordinate engine output with hydraulic demand.

This fault is critical for the PC200LC-8M0 because this model relies on integrated electro-hydraulic control to manage fuel efficiency and hydraulic responsiveness. When the ECM cannot communicate with the hydraulic pump controller, the machine may enter a protective derate mode or experience erratic performance. In used excavators, this communication breakdown often stems from degraded wiring harnesses or corroded connectors rather than failed control modules.

Common Symptoms

• Warning lamp illumination on the instrument cluster, often accompanied by error message display
• Reduced engine power or sudden power loss during operation (limp mode activation)
• Erratic hydraulic response, including inconsistent swing speed or boom/arm movement delays
• Intermittent stalling or difficulty maintaining consistent engine RPM under load
• Monitor display errors showing communication faults or system malfunctions

Potential Causes

The most common causes of Code DAZQKR on used PC200LC-8M0 excavators include:

• Damaged CAN bus wiring harness, particularly at known rub points near the turntable bearing and along the main harness routing under the operator's cab
• Corroded or loose connectors on the ECM or hydraulic controller, especially the 38-pin main harness connector
• Failed terminating resistor on the CAN bus network (120-ohm resistor failure)
• Water intrusion into controller housings from damaged seals or improper previous repairs
• ECM or hydraulic controller software corruption requiring reflashing or module replacement

How to Troubleshoot and Fix Code DAZQKR

Step 1: Visual Inspection Begin by thoroughly inspecting all wiring harnesses between the engine ECM (located behind the operator seat) and the hydraulic controller (mounted near the hydraulic pump). On used machines, check for harness abrasion at the turntable rotation point and where cables pass through bulkheads.

Step 2: Connector Testing Disconnect and inspect all CAN bus connectors for corrosion, bent pins, or moisture. Clean contacts with electrical contact cleaner and check for proper seating. Inspect connector seals for damage—a common issue on machines exceeding 5,000 operating hours.

Step 3: Electrical Measurements Using a digital multimeter, measure CAN High and CAN Low voltage at the ECM connector. You should read approximately 2.5V on CAN High and 2.5V on CAN Low with the key on, engine off. Check terminating resistance between CAN High and CAN Low—it should read 60 ohms (two 120-ohm resistors in parallel).

Step 4: Diagnostic Software Check Connect Komatsu KOMTRAX or compatible diagnostic software to verify communication status and check for stored fault history. Clear codes and monitor for recurrence during a test cycle.

Disclaimer: While this guide provides comprehensive troubleshooting steps, consult a certified Komatsu technician or qualified heavy equipment diesel mechanic for complex electrical repairs, especially on machines still under warranty or service agreements.