Sumitomo SH210-6 Fault Code 1093: Complete Diagnostic Guide

What is Sumitomo SH210-6 Fault Code 1093?

Fault Code 1093 on the Sumitomo SH210-6 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit or a failure in the main relay system. This diagnostic trouble code (DTC) specifically points to an interruption in the data transmission between the ECM and the machine's primary electrical control system, preventing proper engine monitoring and control functions.

This code is critical for the SH210-6's performance because the ECM relies on continuous communication with various sensors and actuators to regulate fuel injection timing, engine speed, and emissions control. When communication fails, the excavator may enter a protective derate mode or experience complete shutdown to prevent potential engine damage. In used excavators, this fault often stems from age-related electrical deterioration rather than component failure.

Common Symptoms

When Code 1093 is active on your Sumitomo SH210-6, operators typically experience:

• Check Engine Light illuminated on the instrument cluster with reduced engine power
• Intermittent or complete loss of engine response to throttle input
• Engine failing to start or shutting down unexpectedly during operation
• ECM not responding to diagnostic tool connection attempts
• Erratic gauge readings or complete instrument panel failure

Potential Causes

The most common technical causes for Code 1093 on used SH210-6 excavators include:

• Main relay failure or poor contact within the relay socket (extremely common on machines with 8,000+ hours)
• Corroded or damaged wiring harness connections at the ECM connector, particularly where the harness routes near the battery box
• Blown fuses in the ECM power supply circuit (typically 20A or 30A fuses in the main fuse panel)
• Failed ECM ground connections due to rust accumulation on chassis mounting points
• Physical damage to the CAN bus wiring from rodent activity or harness chafing against the engine block
• Internal ECM circuit board failure from moisture intrusion (check for previous coolant leaks)

How to Troubleshoot and Fix Code 1093

Step 1: Verify Power Supply to ECM Using a digital multimeter, check for battery voltage (12-14V) at the ECM connector with the key in the ON position. Specifically test pins corresponding to the main power feed. On used excavators, remove the connector and inspect for green corrosion or bent pins before testing.

Step 2: Test Main Relay Operation Locate the main relay in the fuse box (consult service manual for exact position). Listen for an audible click when turning the key to ON. Swap with an identical relay if available, or bench-test resistance across coil terminals (typically 70-90 ohms). Replace if readings are out of specification.

Step 3: Inspect Wiring Harness and Grounds Physically trace the ECM harness from the controller to the engine bay, checking for abraded insulation at known rub points near mounting brackets. Test ground circuit resistance from ECM ground pin to battery negative—readings above 0.5 ohms indicate poor grounding. Clean and re-torque all ground connections.

Step 4: Check CAN Bus Communication If equipped with Sumitomo diagnostic software, monitor real-time communication status. Measure resistance between CAN-High and CAN-Low terminals (should read 60 ohms with terminating resistors). For used machines, moisture in connectors frequently causes intermittent communication failures.

Disclaimer: This guide provides general diagnostic procedures. Always consult the official Sumitomo service manual for your specific serial number range and consider professional assistance for complex electrical diagnostics or ECM replacement.