Sumitomo SH210LC-5LR Fault Code 336: Complete Diagnostic Guide

What is Sumitomo SH210LC-5LR Fault Code 336?

Fault Code 336 on the Sumitomo SH210LC-5LR indicates a malfunction in the Engine Speed Sensor (ESS) circuit or an abnormal signal from the crankshaft position sensor system. This code is triggered when the Electronic Control Module (ECM) detects an intermittent, absent, or out-of-range signal from the sensor responsible for monitoring engine RPM and crankshaft position.

The engine speed sensor is critical for proper fuel injection timing, engine governor operation, and overall performance calibration on this Isuzu-powered excavator model. When this sensor circuit fails, the ECM cannot accurately calculate engine speed, potentially leading to poor fuel economy, rough idling, or complete engine shutdown as a protective measure.

Common Symptoms

When Code 336 is active on your SH210LC-5LR, you may experience:

• Intermittent engine stalling or difficulty starting, especially when the machine is warm
• Check Engine light or fault indicator illuminated on the instrument panel
• Erratic engine RPM readings on the tachometer or complete gauge failure
• Reduced engine power or activation of derate mode limiting maximum RPM
• Rough idling or engine hunting (surging between high and low idle)

Potential Causes

The most common technical causes for Code 336 on used Sumitomo excavators include:

• Damaged or contaminated engine speed sensor due to oil leaks, metal debris, or heat exposure near the flywheel housing
• Corroded or loose electrical connectors at the sensor or ECM harness connection points
• Worn wiring harness with insulation breakdown, particularly where the harness contacts the engine block or frame rails (common rub point on this model)
• Failed crankshaft position sensor (magnetic pickup type) with degraded internal windings
• Excessive air gap between the sensor tip and flywheel teeth due to mounting bracket wear or sensor backing out
• ECM internal fault or corrupted software (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code 336

Step 1: Visual Inspection Begin by locating the engine speed sensor on the flywheel housing (typically driver's side, lower engine area). Inspect the sensor mounting, ensuring it's securely fastened and hasn't backed out. Check the air gap between the sensor tip and flywheel teeth—it should be 0.5-1.5mm. Examine the wiring harness from sensor to ECM for abrasion, cuts, or contact with hot/moving components common in used excavators.

Step 2: Electrical Testing Disconnect the sensor connector and inspect pins for corrosion or bent contacts. Using a digital multimeter, measure sensor resistance across the two terminals—typically 150-300 ohms for this application (consult service manual for exact specification). Test harness continuity from sensor connector to ECM pins, and check for shorts to ground. Verify supply voltage at the harness connector (if applicable to sensor type).

Step 3: Signal Testing and Component Replacement With the sensor reconnected, use Sumitomo diagnostic software or a compatible scan tool to monitor live engine speed signal while cranking. An erratic or absent signal confirms sensor failure. Clean the flywheel ring gear area of debris and oil contamination. Replace the engine speed sensor if resistance or signal tests fail. On used machines, always replace the connector pigtail if corrosion is present—don't just clean it. After replacement, clear codes, perform a stationary regeneration if needed, and road test under load.

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Disclaimer: This guide provides general diagnostic information for experienced technicians. Always consult the official Sumitomo service manual for your specific serial number and year. If you're uncomfortable with electrical diagnostics or lack proper tools, seek assistance from a certified heavy equipment technician to avoid further damage to the ECM or wiring systems.