Liebherr Excavator Fault Code E136: Complete Diagnostic Guide

What is Liebherr Fault Code E136?

Liebherr fault code E136 indicates a malfunction in the engine speed sensor circuit, specifically detecting an implausible signal or communication error between the crankshaft position sensor and the Engine Control Module (ECM). This code triggers when the ECM cannot accurately determine engine RPM due to sensor failure, wiring issues, or signal interference.

The engine speed sensor is critical for Liebherr excavators because it directly controls fuel injection timing, engine protection systems, and power output optimization. Without accurate RPM data, the ECM cannot properly manage combustion cycles, potentially causing catastrophic engine damage if left unaddressed. This fault is particularly common in used excavators with high operating hours where vibration and heat cycling degrade sensor components and wiring harnesses.

Common Symptoms

When code E136 is active, operators typically experience:

• Engine fails to start or cranks without firing due to lack of position reference signal
• Intermittent stalling during operation, especially when machine is cold or under load
• Loss of engine power with activation of derate mode limiting RPM to protect the engine
• Dashboard warning lights illuminated, including check engine lamp and possible system fault indicators
• Erratic tachometer readings showing fluctuating or zero RPM display despite engine running

Potential Causes

The most common technical causes for E136 in used Liebherr excavators include:

• Failed crankshaft position sensor due to heat exposure, oil contamination, or internal component breakdown
• Damaged wiring harness at known rub points near the engine bell housing or flywheel area where vibration causes insulation wear
• Corroded or loose connector pins at the sensor plug, especially in machines exposed to moisture or hydraulic fluid leaks
• Air gap issues between the sensor tip and reluctor ring caused by incorrect installation or mounting bracket failure
• ECM internal fault or corrupted software requiring module reprogramming (less common but possible in older units)
• Flywheel ring gear damage with missing or worn teeth preventing consistent signal generation

How to Troubleshoot and Fix Code E136

Step 1: Visual Inspection Begin by locating the crankshaft position sensor (typically mounted near the flywheel housing on Liebherr diesel engines). Inspect the sensor mounting for security and check the air gap specification (usually 0.5-1.5mm depending on model). Examine the wiring harness from sensor to ECM for obvious damage, chafing points against frame components, or evidence of previous repairs with electrical tape.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. Liebherr sensors typically show 800-1200 ohms at room temperature (consult your specific model's service manual for exact specifications). Check for continuity in the wiring harness and verify there is no short to ground. Inspect connector pins for corrosion or bent contacts—a common issue in used excavators stored outdoors.

Step 3: Signal Testing and Component Replacement Connect Liebherr diagnostic software (LiDat or equivalent) to monitor live sensor signal while cranking the engine. The ECM should receive a consistent AC voltage signal (typically 0.5-5V peak) as the flywheel rotates. If signal is absent or erratic despite good resistance readings, replace the crankshaft position sensor with an OEM or quality aftermarket unit. For used excavators, always apply dielectric grease to connector pins during reassembly to prevent future corrosion. Clear codes and perform a test run under load to verify repair.

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Disclaimer: This guide provides general diagnostic information for Liebherr fault code E136. Always consult your machine's official service manual and manufacturer specifications. Complex electrical issues may require professional diagnosis with factory-level diagnostic equipment. Improper repairs can cause additional damage or safety hazards.