Caterpillar Excavator Fault Code 1141-6: Meaning, Symptoms & Fix

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What is Caterpillar Fault Code 1141-6?

Caterpillar Fault Code 1141-6 indicates a "Current Above Normal" condition on the Engine Speed/Timing Sensor #2 circuit — specifically, the sensor is outputting a current that exceeds the acceptable threshold defined by the Engine Control Module (ECM).

This fault targets the secondary crankshaft/camshaft position sensor circuit, which the ECM relies on to accurately calculate engine timing, fuel injection sequencing, and RPM. On Caterpillar diesel engines, this sensor is mission-critical — an incorrect signal directly compromises combustion efficiency, power output, and emissions compliance.

For used excavators, this code is particularly concerning because aging wiring harnesses and connector corrosion can mimic a failed sensor, leading to unnecessary part replacements.

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Common Symptoms

When Fault Code 1141-6 is active, operators typically experience:

• Active warning lamp illuminated on the instrument cluster (Check Engine or Action light)
• Engine derating — noticeable reduction in power and throttle response
• Rough idle or erratic RPM fluctuation, especially at startup
• Hard starting or no-start condition in severe cases
• Reduced hydraulic performance due to engine management intervention

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Potential Causes

The most likely technical causes for this fault include:

• Short circuit to positive voltage within the sensor signal wire
• Failed Speed/Timing Sensor #2 — internal short causing excessive current draw
• Damaged or chafed wiring harness — particularly where the harness routes near the engine block or chassis brackets (a known wear point on high-hour Caterpillar machines)
• Corroded or moisture-contaminated connector pins at the sensor or ECM interface
• Faulty ECM — rare, but possible on machines with prior electrical damage or improper repairs

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How to Troubleshoot and Fix Code 1141-6

Step 1 — Perform a Visual Harness Inspection Begin with a thorough physical inspection of the wiring harness running to Sensor #2. On used excavators, look specifically for harness chafing against metal brackets, heat shields, or hose clamps. Check connector pins for corrosion, green oxidation, or moisture intrusion before assuming sensor failure.

Step 2 — Measure Circuit Voltage and Resistance Using a digital multimeter, disconnect the sensor connector and measure voltage on the signal wire with the key-on. Acceptable supply voltage is typically 5V DC reference; a reading significantly above this confirms a short to power. Check resistance to ground — a reading near zero ohms indicates a direct short in the harness.

Step 3 — Use Cat ET Diagnostic Software Connect Caterpillar Electronic Technician (Cat ET) software to monitor live sensor data and confirm active fault status. Use the "Wiggle Test" function within Cat ET while manipulating the harness to isolate intermittent shorts — a common finding on high-hour machines.

Step 4 — Replace and Verify Only after confirming harness integrity should you replace Sensor #2. After replacement, clear codes via Cat ET and perform a full engine warm-up cycle to verify the fault does not return.

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Disclaimer: This guide is intended for informational purposes for qualified mechanics and experienced equipment owners. Always consult a certified Caterpillar dealer or licensed heavy equipment technician before performing repairs, particularly on machines under warranty or in safety-critical applications.