Sumitomo SH80-6B Fault Code P0119-2: Complete Diagnostic Guide

What is Sumitomo SH80-6B Fault Code P0119-2?

Fault Code P0119-2 indicates an Engine Coolant Temperature (ECT) sensor circuit intermittent or erratic signal detected by the Engine Control Module (ECM). This code specifically means the ECT sensor is sending voltage readings that fluctuate outside the expected range or pattern during engine operation, suggesting an unstable electrical connection rather than a consistent out-of-range value.

This code is critical for the SH80-6B's performance because the ECM relies on accurate coolant temperature data to manage fuel injection timing, idle speed control, and engine protection protocols. An intermittent signal prevents proper engine warm-up cycles and can trigger unnecessary derate modes that limit hydraulic performance and digging power.

Common Symptoms

When P0119-2 is active on your Sumitomo SH80-6B, you may experience:

• Check Engine Light or malfunction indicator illuminated on the instrument panel
• Erratic engine idle speed, especially during cold starts or warm-up periods
• Intermittent loss of hydraulic power or sluggish boom/arm response
• Engine cooling fan running continuously at high speed regardless of actual temperature
• Hard starting conditions when the engine is warm (ECM misreads temperature status)

Potential Causes

The most common technical reasons for P0119-2 on used excavators include:

• Corroded or loose connector terminals at the ECT sensor (common failure point after 3,000+ operating hours)
• Damaged sensor wiring harness due to heat exposure near the exhaust manifold or rubbing against engine components
• Failing ECT sensor with internal resistance breakdown causing intermittent signal dropout
• ECM ground circuit issues or poor chassis ground connections (typical in machines operating in wet/muddy conditions)
• Contaminated coolant causing sensor element degradation or buildup on the sensor tip

How to Troubleshoot and Fix Code P0119-2

Step 1: Visual Inspection Locate the ECT sensor (typically mounted on the engine block near the thermostat housing). Inspect the connector for corrosion, moisture intrusion, or bent pins. On used excavators, check for harness chafing where wires route near moving components or hot surfaces.

Step 2: Electrical Testing Using a digital multimeter, backprobe the ECT sensor connector with the engine at operating temperature. The sensor should read approximately 2,000-3,000 ohms at 80°F and 200-300 ohms at 200°F. Watch for fluctuating resistance that indicates internal sensor failure.

Step 3: Wiring Continuity Check Disconnect the sensor and measure resistance between the sensor signal wire and ECM pin (consult service manual for specific terminal). Reading should be less than 5 ohms. Check for short circuits to ground (should read infinite resistance).

Step 4: Connector Repair or Replacement Clean all connector terminals with electrical contact cleaner and apply dielectric grease. Replace damaged harness sections and secure wiring away from heat sources using proper heat-resistant loom.

Step 5: Sensor Replacement If testing confirms sensor failure, replace with OEM-equivalent ECT sensor and torque to specification (typically 10-15 ft-lbs). Clear codes and perform a heat cycle test.

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Disclaimer: This guide provides general diagnostic procedures. Always consult the Sumitomo SH80-6B service manual for model-specific specifications. If you lack proper diagnostic tools or experience with electrical systems, consult a certified heavy equipment technician to avoid misdiagnosis or component damage.