Sumitomo SH300-6 Fault Code 7248: Complete Diagnostic Guide

What is Sumitomo SH300-6 Fault Code 7248?

Fault Code 7248 on the Sumitomo SH300-6 excavator indicates a hydraulic pump control system malfunction, specifically a communication error between the Engine Control Module (ECM) and the pump controller or an abnormal signal from the pump displacement sensor.

This diagnostic trouble code (DTC) signals that the electronic control system cannot properly regulate hydraulic pump output, which is critical for the SH300-6's load-sensing hydraulic system. The fault typically originates from the pump Electronic Control Unit (ECU), wiring harness damage, or sensor degradation. Since the SH300-6 relies on precise pump displacement control to match hydraulic demand with engine power, this code can significantly impact fuel efficiency and operational performance.

Common Symptoms

When Code 7248 is active, operators typically experience:

• Reduced hydraulic power across all functions (boom, arm, bucket, swing)
• Warning light illumination on the instrument cluster, often accompanied by audible alarm
• Inconsistent hydraulic response or sluggish movement during combined operations
• Engine derating or limited RPM range as the ECM enters protective mode
• Intermittent loss of hydraulic functions that may reset after machine shutdown

Potential Causes

The most common technical causes for Code 7248 on used SH300-6 excavators include:

• Pump displacement sensor failure due to internal wear or contamination from hydraulic fluid degradation
• Wiring harness damage at flex points near the pump mounting area, especially where cables route along the engine-to-pump interface
• Corroded or loose connector pins at the pump ECU harness connection (C-connector series)
• Hydraulic pump ECU malfunction from moisture ingress or electronic component aging
• CAN bus communication errors between the main controller and pump controller
• Voltage supply issues to the pump control system (typically 12V or 24V depending on configuration)

How to Troubleshoot and Fix Code 7248

Step 1: Connect Diagnostic Software Use Sumitomo-compatible diagnostic software (or universal heavy equipment scanners supporting J1939 protocol) to verify the active fault code and check freeze frame data. Document pump displacement values and voltage readings at the time of fault occurrence.

Step 2: Inspect Wiring Harness and Connectors Physically examine the pump controller harness, particularly at known wear points where cables contact the hydraulic tank or swing bearing. On used excavators, look for abraded insulation, oil contamination on connectors, and corrosion on terminal pins. Clean all connections with electrical contact cleaner and apply dielectric grease.

Step 3: Test Pump Displacement Sensor Using a digital multimeter, measure the sensor output voltage (typically 0.5-4.5V range). Compare readings against Sumitomo specifications while manually moving the pump swashplate if accessible. Replace the displacement sensor if readings are erratic or out of range.

Step 4: Verify Power Supply and Ground Circuits Check voltage supply to the pump ECU (should be battery voltage ±0.5V) and verify ground circuit resistance is below 1 ohm. Poor grounds are common in high-hour machines due to corrosion buildup.

Step 5: Perform CAN Bus Communication Test Test CAN-High and CAN-Low signals between the main ECM and pump controller. Resistance should measure approximately 60 ohms across the network. Replace damaged sections of the communication harness if necessary.

Disclaimer: This guide provides general troubleshooting steps for informational purposes. Always consult the official Sumitomo service manual for your specific serial number and engage qualified hydraulic technicians for complex repairs. Improper diagnostics can cause additional system damage.