Komatsu PC650LC-8R Fault Code AB00KE: Complete Diagnostic Guide

What is Komatsu PC650LC-8R Fault Code AB00KE?

Fault Code AB00KE indicates an abnormality in the hydraulic pump control system, specifically related to the pump flow control solenoid valve circuit or its associated sensors. This code is triggered when the Electronic Control Module (ECM) detects irregular voltage, current draw, or signal response from the pump control circuit that regulates hydraulic flow distribution.

In the PC650LC-8R model, this system is critical for maintaining optimal hydraulic performance across all functions. The pump flow control directly affects bucket speed, arm force, and swing torque. When this code activates, the machine typically enters a protective derate mode to prevent damage to the hydraulic system or pump components. For used excavators, this fault often stems from age-related electrical degradation rather than mechanical pump failure.

Common Symptoms

When Code AB00KE is active, operators typically experience:

• Amber warning light illuminated on the monitor panel with reduced hydraulic responsiveness
• Sluggish hydraulic functions across multiple circuits, particularly noticeable in combined operations (e.g., boom lift while swinging)
• Intermittent power loss during high-demand tasks, with the machine recovering after brief idle periods
• Error message display on the multi-function monitor indicating pump system malfunction
• Unusual hydraulic pump noise or pressure fluctuations during operation

Potential Causes

The most common technical causes for AB00KE in used PC650LC-8R excavators include:

• Faulty pump control solenoid valve with internal coil resistance outside specification (typically 8-12 ohms)
• Damaged wiring harness near the main pump area where cables experience vibration and heat exposure
• Corroded or loose connector pins at the pump solenoid connection point (C-connector series)
• Failed pressure sensor providing incorrect feedback to the ECM about actual pump output
• ECM internal fault in the pump control driver circuit (less common but possible in high-hour machines)
• Contaminated hydraulic oil causing solenoid valve sticking or erratic operation

How to Troubleshoot and Fix Code AB00KE

Step 1: Initial Inspection and Data Retrieval Connect Komatsu KOMTRAX diagnostic software or a compatible scan tool to retrieve freeze-frame data. Note the operating conditions when the fault occurred. Visually inspect the pump control solenoid valve and associated wiring harness for obvious damage, oil contamination, or connector corrosion.

Step 2: Electrical Testing Using a digital multimeter, disconnect the pump solenoid connector and measure coil resistance (should read 8-12 ohms at 20°C). Check for supply voltage at the harness side (should show battery voltage with key on). Inspect connector pins for bent terminals or green corrosion—a common issue in used excavators operating in humid environments.

Step 3: Harness and Ground Verification Trace the wiring harness from the solenoid to the ECM, paying special attention to rub points near the pump mounting bracket and along the chassis rail. Perform a voltage drop test on ground circuits (should be less than 0.1V). Check harness continuity and insulation resistance to ground (minimum 10kΩ).

Step 4: Component Testing and Replacement If electrical tests pass, perform a functional test of the solenoid valve using the diagnostic software's actuator test function. Replace the solenoid if it fails to respond or shows erratic behavior. For used excavators with over 8,000 hours, consider replacing the entire pump control valve assembly as internal wear may cause intermittent faults.

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific machine serial number and seek professional assistance from certified technicians for complex repairs involving hydraulic or electrical systems.