What is Sumitomo SH220LC-5 Fault Code 2104?

Fault Code 2104 on the Sumitomo SH220LC-5 excavator indicates a Boost Pressure Sensor Circuit malfunction or abnormal turbocharger boost pressure reading. This code is triggered when the Engine Control Module (ECM) detects voltage signals from the boost pressure sensor that fall outside the expected operating range, typically either too high or too low compared to normal engine load conditions.

The boost pressure sensor monitors the air pressure generated by the turbocharger and sends real-time data to the ECM. This information is critical for proper fuel injection timing, air-fuel ratio optimization, and overall engine performance. On the SH220LC-5's diesel engine, maintaining accurate boost pressure readings ensures maximum power output, fuel efficiency, and emissions compliance. When this sensor circuit fails or provides faulty data, the ECM cannot properly regulate engine performance, potentially leading to reduced power and increased fuel consumption.

Common Symptoms

When Code 2104 is active on your Sumitomo SH220LC-5, you may experience:

• Check Engine Light or warning indicator illuminated on the dashboard
• Noticeable loss of engine power or reduced hydraulic performance, especially under heavy loads
• Engine derating or entering a limp mode to protect internal components
• Black smoke from the exhaust indicating improper air-fuel mixture
• Rough idling or hesitation during acceleration when operating attachments

Potential Causes

The most common technical reasons for Code 2104 on used SH220LC-5 excavators include:

• Faulty boost pressure sensor due to age, contamination, or internal component failure
• Damaged or corroded wiring harness connecting the sensor to the ECM (common near engine heat sources or moving components)
• Loose or corroded electrical connectors at the sensor or ECM terminals
• Turbocharger mechanical issues causing actual abnormal boost pressure (worn bearings, damaged impeller, or leaking seals)
• Intake air leaks between the turbocharger and intake manifold affecting pressure readings
• ECM software glitches or internal ECM failures (less common but possible on older machines)

How to Troubleshoot and Fix Code 2104

Step 1: Visual Inspection Begin by locating the boost pressure sensor (typically mounted on the intake manifold near the turbocharger). Inspect the wiring harness for visible damage, rubbing, melting, or oil contamination—especially where the harness passes near hot exhaust components or moving engine parts. On used excavators, check all electrical connectors for corrosion, bent pins, or moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, disconnect the boost pressure sensor and measure the reference voltage from the ECM (typically 5 volts). Then check the sensor's internal resistance according to Sumitomo specifications (usually between 1-5 kΩ depending on temperature). Test the signal wire continuity back to the ECM and verify the ground circuit has less than 0.5 ohms resistance.

Step 3: Sensor and System Verification If electrical checks pass, connect Sumitomo diagnostic software or a compatible scan tool to monitor live boost pressure data. Compare actual readings with expected values at idle and under load. Physically inspect the turbocharger for shaft play, oil leaks, or damaged compressor blades. Check all intake system clamps and gaskets for air leaks that could cause false pressure readings.

Step 4: Component Replacement Replace the boost pressure sensor if readings are erratic or out of specification. For used excavators with high hours, consider replacing the entire sensor harness if any corrosion or wear is present, as intermittent connections often cause recurring codes. Clear the fault code and perform a test cycle under normal operating conditions.

---

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