Sumitomo SH210-5 Fault Code 601: Complete Diagnostic Guide

What is Sumitomo SH210-5 Fault Code 601?

Fault Code 601 on the Sumitomo SH210-5 excavator indicates a Pump Control System malfunction, specifically related to the Electronic Control Unit (ECU) detecting abnormal signals from the hydraulic pump displacement sensor or control circuit. This code is part of Sumitomo's proprietary diagnostic system that monitors the load-sensing hydraulic system critical to this model's performance.

The hydraulic pump displacement sensor provides real-time feedback to the ECU about pump swash plate angle and flow demand. When the ECU receives voltage signals outside the normal range (typically 0.5-4.5V), it triggers Code 601 and may limit pump output to protect the system. This is particularly critical on the SH210-5 because its load-sensing system directly affects both productivity and fuel efficiency.

Common Symptoms

When Code 601 is active, operators typically experience:

• Sudden loss of hydraulic power across all functions (boom, arm, bucket, swing)
• Intermittent or complete derate mode where the machine operates at significantly reduced capacity
• Warning lamp illumination on the instrument cluster (often amber or red hydraulic system light)
• Erratic hydraulic response where functions may work normally then suddenly lose power
• Increased engine RPM without corresponding hydraulic output as the ECU attempts to compensate

Potential Causes

The most common technical causes for Code 601 on used SH210-5 excavators include:

• Worn or failed pump displacement sensor (common after 6,000+ operating hours)
• Corroded or damaged wiring harness at the main pump connection point, especially where the harness routes near the swing motor
• ECU internal faults or corrupted calibration data from voltage spikes
• Contaminated hydraulic oil causing sensor drift or sticking control valves
• Loose or corroded ground connections at the pump controller module
• Physical damage to sensor mounting from vibration or previous repairs

How to Troubleshoot and Fix Code 601

Step 1: Initial Visual Inspection Begin by inspecting the main pump harness for obvious damage, particularly where it passes through the upper structure near pivot points. Check all connector terminals for corrosion, bent pins, or oil contamination. On used excavators, this harness area is prone to chafing.

Step 2: Sensor Voltage Testing Using a multimeter, backprobe the pump displacement sensor connector (typically a 3-pin Deutsch connector on the pump body). With the ignition on but engine off, verify the supply voltage reads 5V ±0.25V and the signal wire shows approximately 2.5V at rest. Compare readings against Sumitomo specifications.

Step 3: Resistance and Ground Checks Measure sensor resistance (should be 1-3 kΩ depending on temperature) and verify ground circuit continuity (less than 1Ω to chassis ground). Check for voltage drop on ground circuits under load.

Step 4: Dynamic Testing If static tests pass, use Sumitomo diagnostic software (or compatible scan tool) to monitor live sensor data during operation. Look for signal dropout, erratic voltage swings, or values that don't correlate with actual pump demand.

Step 5: Component Replacement Priority For used machines, replace components in this order: sensor connector/pigtail repair, displacement sensor itself, then wiring harness sections. Always clear codes and recalibrate the ECU after repairs using manufacturer procedures.

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Disclaimer: This guide provides general diagnostic information. Hydraulic system repairs involve high pressures and electrical systems. Always consult the official Sumitomo service manual and consider professional assistance for complex diagnostics or if you're unfamiliar with hydraulic troubleshooting procedures.