Sumitomo SH200-5 Fault Code 0606: Complete Diagnostic Guide

What is Sumitomo SH200-5 Fault Code 0606?

Fault Code 0606 on the Sumitomo SH200-5 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit or a failure in the engine speed sensor signal. This diagnostic trouble code is triggered when the ECM detects an abnormal or absent signal from the crankshaft position sensor or engine speed sensor, which is critical for proper fuel injection timing and engine management.

The engine speed sensor provides essential data to the ECM about crankshaft rotation speed and position. Without accurate input from this sensor, the fuel injection system cannot optimize combustion timing, potentially causing poor performance, rough idling, or complete engine shutdown. For used excavators like the SH200-5, this fault often stems from age-related sensor degradation or wiring harness issues common in machines with extensive operating hours.

Common Symptoms

When Code 0606 is active on your SH200-5, you may experience:

• Engine warning light illuminated on the instrument cluster or complete engine shutdown
• Difficulty starting the engine or extended cranking time before ignition
• Rough idling or unstable engine RPM, particularly at low speeds
• Loss of engine power or failure to reach maximum operating RPM
• Intermittent stalling during operation, especially under load or during hydraulic functions

Potential Causes

The most common causes of Code 0606 on used Sumitomo SH200-5 excavators include:

• Failed or degraded engine speed sensor due to heat exposure and vibration over time
• Damaged wiring harness between the speed sensor and ECM, particularly at flex points near the engine mount
• Corroded or loose electrical connectors at the sensor or ECM terminals
• Contaminated sensor face from oil leaks, metal debris, or dirt buildup affecting magnetic signal
• Damaged tone ring (reluctor wheel) on the crankshaft with missing or worn teeth
• ECM internal fault or water intrusion into the control module housing
• Poor grounding at the ECM or sensor mounting points

How to Troubleshoot and Fix Code 0606

Step 1: Visual Inspection Begin by locating the engine speed sensor (typically mounted on the engine block near the flywheel or front timing cover). Inspect the sensor mounting for security, check for oil contamination on the sensor face, and examine the wiring harness for obvious damage, chafing, or connector corrosion. On used machines, pay special attention to harness routing near moving components or heat sources.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. Most engine speed sensors should read between 150-1000 ohms (consult your service manual for exact specifications). Check for continuity in the wiring from sensor to ECM, and verify proper ground voltage (less than 0.5V). Inspect connectors for bent pins or moisture.

Step 3: Signal Testing and Component Replacement With the engine cranking, use an oscilloscope or AC voltage setting on your multimeter to verify the sensor produces an alternating voltage signal. If no signal is present despite proper resistance, replace the speed sensor. If the sensor tests properly, inspect the tone ring for damage and test ECM functionality using Sumitomo diagnostic software or compatible scan tool.

For used excavators, always clean connector terminals with electrical contact cleaner and apply dielectric grease before reconnecting. After repairs, clear the fault code and perform a test operation cycle to verify the fix.

---

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