Sumitomo SH350HD-5 Fault Code 117: Complete Diagnostic Guide

What is Sumitomo SH350HD-5 Fault Code 117?

Fault Code 117 on the Sumitomo SH350HD-5 excavator indicates a Boost Pressure Sensor Circuit malfunction or abnormal turbocharger boost pressure reading. This code is triggered when the Electronic Control Module (ECM) detects a signal from the boost pressure sensor that falls outside the manufacturer's specified voltage range or when actual boost pressure deviates significantly from expected values during engine operation.

The boost pressure sensor monitors intake manifold pressure after the turbocharger compresses incoming air. This data is critical for the ECM to calculate proper fuel injection timing and quantity. On the SH350HD-5's diesel engine, accurate boost pressure readings ensure optimal combustion efficiency, emission control, and prevent over-boost conditions that could cause catastrophic engine damage. When this sensor fails or provides erratic data, the machine may enter a protective derate mode to prevent engine harm.

Common Symptoms

When Code 117 is active on your SH350HD-5, operators typically experience:

• Check Engine Light or Warning Lamp illuminated on the instrument cluster
• Noticeable loss of engine power, particularly under load or during high-demand operations like digging or lifting
• Black smoke from the exhaust indicating improper air-fuel mixture calculations
• Engine operating in limp mode with restricted RPM or hydraulic flow reduction
• Intermittent power surges or hesitation during acceleration as the ECM attempts to compensate for faulty sensor data

Potential Causes

Several factors commonly trigger Code 117 on used excavators, especially machines with significant operating hours:

• Boost pressure sensor failure due to heat exposure, vibration, or internal component degradation
• Damaged or corroded wiring harness between the sensor and ECM, particularly at connector pins exposed to moisture
• Intake air leaks downstream of the turbocharger allowing unmetered air to enter the manifold
• Turbocharger malfunction causing actual boost pressure irregularities (worn bearings, damaged compressor wheel)
• ECM software glitches or corrupted calibration data (less common but possible on older machines)
• Connector contamination from oil vapor or dirt intrusion at the sensor plug

How to Troubleshoot and Fix Code 117

Step 1: Visual Inspection Begin with a thorough examination of the boost pressure sensor located on the intake manifold. Check the wiring harness for obvious damage, chafing against metal edges, or connector corrosion. On used excavators, pay special attention to harness routing near hot exhaust components where insulation may have deteriorated.

Step 2: Electrical Testing Using a digital multimeter, perform voltage checks at the sensor connector with the ignition on (engine off). The reference voltage should typically read 5 volts from the ECM. Check sensor signal voltage at idle and compare against manufacturer specifications. Measure resistance across sensor terminals (typically 1-3 kΩ depending on temperature).

Step 3: Live Data Analysis Connect Sumitomo diagnostic software or compatible scan tool to monitor real-time boost pressure readings. Compare actual values against expected boost levels during engine rev-up. Discrepancies indicate sensor failure, while consistent zero readings suggest wiring issues.

Step 4: Component Replacement If electrical tests confirm sensor failure, replace the boost pressure sensor with OEM or quality aftermarket parts. Clean connector terminals with electrical contact cleaner before installation. After replacement, clear codes and perform a test cycle under load.

For Used Equipment Note: Before replacing expensive components, pressure-test the intake system for leaks and inspect turbocharger operation. Many Code 117 instances on high-hour machines stem from mechanical issues rather than sensor failure.

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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 repairs. Improper repairs may void warranties or cause safety hazards.