Sumitomo SH210-6 Fault Code 238: Complete Diagnostic Guide

What is Sumitomo SH210-6 Fault Code 238?

Fault Code 238 on the Sumitomo SH210-6 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit or a failure in the machine's CAN (Controller Area Network) bus system. This code specifically signals that the ECM is unable to properly communicate with other control units, particularly the hydraulic controller or display module.

This communication breakdown is critical because the SH210-6 relies on integrated electronic systems to coordinate engine performance with hydraulic functions. When CAN bus communication fails, the machine cannot properly regulate fuel delivery, hydraulic pressure, or diagnostic information display, potentially leading to unsafe operating conditions or complete machine shutdown.

Common Symptoms

When Code 238 is active on your Sumitomo SH210-6, operators typically experience:

• Warning lights illuminated on the instrument panel, often accompanied by reduced engine power
• Intermittent or complete loss of hydraulic function responsiveness
• Erratic gauge readings or complete failure of the digital display panel
• Engine derate mode activated, limiting RPM to protect the machine
• Difficulty starting or unexpected engine shutdown during operation

Potential Causes

The most common technical causes for Code 238 on used SH210-6 excavators include:

• Damaged or corroded CAN bus wiring harness connections, particularly at harness junction points near the engine compartment
• Faulty ECM ground connections or degraded ground straps due to age and vibration
• Water intrusion into controller connectors, common in machines with worn cab seals
• Failed ECM or hydraulic controller module, especially in high-hour machines
• Broken or shorted CAN bus termination resistors (120-ohm resistors at network endpoints)
• Physical harness damage from rubbing against frame components—a known issue on the SH210-6 near the swing bearing area

How to Troubleshoot and Fix Code 238

Step 1: Visual Inspection Begin with a thorough harness inspection along the entire CAN bus network. On used excavators, check for wire chafing near the swing post, engine mounts, and hydraulic pump areas. Inspect all connector pins for corrosion, bent terminals, or moisture intrusion. Clean connections with electrical contact cleaner.

Step 2: Electrical Testing Using a digital multimeter, measure CAN-High and CAN-Low voltage at the ECM connector (typically terminals 15 and 16). With ignition on, engine off, you should read approximately 2.5V on both lines. Check termination resistor continuity—you should measure 60 ohms between CAN-High and CAN-Low with all modules connected (two 120-ohm resistors in parallel).

Step 3: Ground Circuit Verification Verify ECM ground integrity by measuring resistance between ECM ground terminals and battery negative—it should be less than 0.5 ohms. On used machines, clean and re-torque all ground connections, particularly the main engine ground strap.

Step 4: Advanced Diagnostics If basic checks pass, use Sumitomo diagnostic software or compatible J1939 scan tools to monitor real-time CAN bus traffic. Intermittent codes often indicate failing modules or loose connections that require further isolation testing by disconnecting modules one at a time.

For used excavators, replacing the entire main harness may be necessary if multiple chafe points exist—a common issue on machines exceeding 8,000 hours.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual and consider professional diagnostic assistance for complex electrical issues. Improper repairs may cause additional system damage.