What is Komatsu PC240LC-10 Fault Code CA1695?

Fault Code CA1695 indicates a malfunction in the Engine Speed Sensor 2 Circuit on the Komatsu PC240LC-10 excavator. This code is triggered when the Engine Control Module (ECM) detects an abnormal signal or loss of communication from the secondary engine speed sensor, which monitors crankshaft rotation and provides critical data for fuel injection timing and engine synchronization.

The Komatsu PC240LC-10 utilizes a dual-sensor system for engine speed monitoring to ensure operational safety and precision. When Engine Speed Sensor 2 fails or sends inconsistent signals, the ECM cannot accurately manage fuel delivery, potentially causing performance degradation or engine protection mode activation. This is particularly critical in used machines where sensor degradation from heat cycles, vibration exposure, and contamination is common.

Common Symptoms

When CA1695 is active on your PC240LC-10, operators typically experience:

• Check Engine Warning Light illuminated on the instrument cluster with possible audible alarm
• Engine power derate or limiting to reduced RPM as a protective measure
• Rough idle or inconsistent engine speed, particularly noticeable during low-load operations
• Difficulty starting or extended cranking time, especially in cold conditions
• Intermittent loss of power during operation, which may resolve temporarily before recurring

Potential Causes

The most common technical causes for Code CA1695 on used PC240LC-10 excavators include:

• Failed or degraded Engine Speed Sensor 2 due to heat exposure or internal component breakdown
• Damaged sensor wiring harness caused by rubbing against the engine block or frame (known vulnerability point near the flywheel housing on this model)
• Corroded or loose electrical connectors at the sensor or ECM connection points from moisture intrusion
• Broken or damaged reluctor ring on the crankshaft (rare but possible in high-hour machines)
• ECM internal fault or poor ground connection affecting sensor circuit integrity
• Oil or debris contamination on the sensor face interfering with magnetic pickup

How to Troubleshoot and Fix Code CA1695

Step 1: Visual Inspection Begin with a thorough inspection of Engine Speed Sensor 2 located near the flywheel housing on the transmission side. Check for physical damage, oil contamination on the sensor tip, and examine the wiring harness for signs of chafing, particularly where it routes along the engine block. On used excavators, inspect all electrical connectors for corrosion, bent pins, or moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, check sensor resistance (typically 190-250 ohms for Komatsu sensors, but verify with service manual). Disconnect the sensor and measure resistance across the sensor terminals. Next, check for supply voltage at the harness connector (should read approximately 5-12V with key on). Inspect continuity from sensor connector to ECM pins, looking for opens or shorts to ground.

Step 3: Signal Testing and Replacement Connect Komatsu diagnostic software (KOMTRAX or compatible scan tool) to monitor live sensor data. Crank the engine and verify that Sensor 2 produces a frequency signal. If no signal appears or readings are erratic, replace the sensor. For used machines, always apply dielectric grease to connectors during reassembly to prevent future corrosion. Clear codes and perform a test cycle under load to confirm repair.

Used Equipment Note: Before replacing the sensor, carefully inspect harness routing for wear points specific to the PC240LC-10—the harness near the starter motor is particularly susceptible to heat and vibration damage on higher-hour machines.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific machine serial number and seek professional assistance for complex electrical diagnostics or if unfamiliar with high-voltage systems.