Sany SY245/265H Fault Code 117: Complete Diagnostic Guide

What is Sany SY245/265H Fault Code 117?

Fault Code 117 indicates a Fuel Injection Pump Control Circuit malfunction in the Mitsubishi Heavy Industries diesel engine. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects abnormal voltage or resistance in the circuit controlling the fuel injection pump's solenoid actuator.

The fuel injection pump control circuit regulates precise fuel delivery timing and volume to the engine cylinders. When this circuit malfunctions, the ECM cannot properly manage fuel injection parameters, directly impacting combustion efficiency, engine power output, and emissions compliance. For the Mitsubishi-powered SY245/265H excavators, this code is critical because improper fuel delivery can cause immediate performance degradation and potential engine damage.

Common Symptoms

When Code 117 is active, operators typically experience:

• Engine power derate or sudden loss of hydraulic power during operation
• Rough idling or irregular engine RPM fluctuations, particularly at low speeds
• Black or excessive exhaust smoke indicating incomplete combustion
• Hard starting conditions or extended cranking time, especially when cold
• Illuminated warning lights on the instrument cluster with possible engine shutdown protection mode

Potential Causes

The most common technical causes for Code 117 in used SY245/265H excavators include:

• Faulty fuel injection pump solenoid due to internal coil degradation or mechanical sticking
• Damaged wiring harness between the ECM and injection pump, particularly at flex points near the engine mount where vibration causes wire fatigue
• Corroded or loose electrical connectors at the injection pump—common in machines with high operating hours in dusty or wet environments
• ECM internal driver circuit failure affecting fuel pump control output
• Poor ground connections at the engine block or chassis ground points
• Contaminated fuel causing deposits on injection pump components and affecting solenoid operation

How to Troubleshoot and Fix Code 117

Step 1: Visual Inspection Begin by thoroughly inspecting the wiring harness from the ECM to the fuel injection pump. On used excavators, check for harness abrasion against the engine block, cracked insulation, or evidence of previous repairs. Examine all connector terminals for corrosion, bent pins, or moisture intrusion—clean with electrical contact cleaner if needed.

Step 2: Electrical Testing Using a digital multimeter, measure the resistance of the fuel injection pump solenoid (typically 2-5 ohms for Mitsubishi pumps—consult service manual for exact specifications). Disconnect the harness connector and test solenoid resistance at the pump side. Next, check for voltage supply at the connector with the ignition on—you should see battery voltage (approximately 12V) on the supply wire.

Step 3: Circuit Continuity Check Test continuity between the ECM connector pins and the injection pump connector to identify any open circuits or high-resistance connections. Pay special attention to ground circuits, as poor grounds are frequently overlooked in used machinery diagnostics.

Step 4: Component Testing If electrical tests pass, the injection pump solenoid actuator itself may be mechanically faulty. Consider swap-testing with a known-good component if available, or use Mitsubishi diagnostic software (MUT-III or compatible) to perform active tests commanding the solenoid on/off while monitoring current draw.

Step 5: Advanced Diagnostics For persistent codes after component replacement, suspect ECM driver circuit failure or internal fuel system contamination requiring injection pump removal and bench testing.

Critical Note for Used Equipment: Before replacing expensive components like injection pumps or ECMs, verify that all connectors are sealed properly and that previous owners haven't installed aftermarket wiring that may not meet OEM specifications.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sany service manual and Mitsubishi engine technical documentation for your specific machine serial number. Complex fuel system repairs should be performed by certified technicians with proper diagnostic equipment.