What is Komatsu PC240LC-8 Fault Code E-16?

Fault Code E-16 on the Komatsu PC240LC-8 indicates a malfunction in the hydraulic oil temperature sensor circuit. This diagnostic trouble code is triggered when the Engine Control Module (ECM) detects an abnormal voltage signal from the hydraulic oil temperature sensor, typically indicating an open circuit, short circuit, or sensor failure.

The hydraulic oil temperature sensor plays a critical role in protecting the hydraulic system by monitoring fluid temperatures and preventing overheating damage to pumps, motors, and seals. When the ECM cannot accurately read hydraulic oil temperature, it may limit machine performance or activate protection modes to prevent catastrophic hydraulic system failure. For used excavators like the PC240LC-8, this sensor and its associated wiring are particularly vulnerable to corrosion, vibration damage, and connector degradation after thousands of operating hours.

Common Symptoms

• Yellow warning light illuminated on the instrument cluster with E-16 displayed on the monitor panel
• Reduced hydraulic performance or automatic derate mode limiting swing speed and boom/bucket response
• Intermittent temperature gauge readings or complete loss of hydraulic temperature display
• Increased fan operation as the ECM defaults to maximum cooling due to inability to read actual temperature
• Machine may enter limited function mode preventing operation until the fault is addressed

Potential Causes

The E-16 code on used PC240LC-8 excavators typically stems from age-related failures:

• Hydraulic oil temperature sensor failure due to internal element degradation (common after 6,000+ hours)
• Damaged or corroded wiring harness at flex points near the hydraulic tank or along the chassis rail
• Loose or corroded electrical connectors at the sensor or ECM junction points (moisture intrusion is common)
• Broken or chafed sensor wires caused by rubbing against the hydraulic tank mounting brackets
• ECM internal fault (rare, but possible in high-hour machines with electrical system history)

How to Troubleshoot and Fix Code E-16

Step 1: Visual Inspection Begin with a thorough physical examination of the hydraulic oil temperature sensor located on the hydraulic oil tank. Check the sensor body for cracks, oil contamination on the connector, and physical damage. Inspect the wiring harness from sensor to ECM, paying special attention to known rub points where the harness passes near the tank mounting hardware and along the right-side chassis rail.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. At room temperature (20°C/68°F), the sensor should read approximately 2,000-3,000 ohms (consult your service manual for exact specifications). Check for continuity in the wiring harness from sensor connector to ECM pins. Measure voltage supply from the ECM—you should see approximately 5 volts on the reference wire with ignition on.

Step 3: Connector and Harness Repair For used excavators, carefully clean all connector pins using electrical contact cleaner and inspect for green corrosion or bent pins. Apply dielectric grease to prevent future moisture intrusion. If wiring shows wear at friction points, repair with heat-shrink solder connections and reroute away from sharp edges using proper loom protection.

Step 4: Component Replacement If testing confirms sensor failure, replace with a genuine Komatsu hydraulic temperature sensor (Part #7861-93-3320 or equivalent). After installation, clear codes using Komatsu diagnostic software (KOMTRAX) or a compatible diagnostic scanner, then cycle the ignition and verify the code does not return. Monitor hydraulic temperature readings during a test operation cycle.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific serial number and consider professional diagnostic services for complex electrical issues, especially on used equipment with unknown maintenance history.