Komatsu PC210-7 Fault Code E246: Technical Guide

What is Komatsu PC210-7 Fault Code E246?

Fault Code E246 indicates a malfunction in the Exhaust Temperature Sensor Circuit, specifically detecting an abnormal voltage signal from the exhaust gas temperature sensor located in the diesel particulate filter (DPF) system. This code triggers when the Engine Control Module (ECM) receives a voltage reading outside the expected range of 0.5-4.5 volts from the temperature sensor monitoring post-combustion exhaust temperatures.

The exhaust temperature sensor plays a critical role in the PC210-7's emissions control system by monitoring DPF regeneration cycles. When this sensor fails, the ECM cannot properly manage the active regeneration process, potentially leading to DPF clogging, reduced engine power, and increased fuel consumption. For used excavators, this code often appears due to sensor degradation or harness damage from prolonged heat exposure.

Common Symptoms

• Check Engine Light illuminated on the monitor panel with reduced engine power (derate mode activated)
• Frequent or incomplete DPF regeneration cycles, causing the machine to enter stationary regeneration more often than normal
• Black smoke from the exhaust during acceleration or heavy load operation
• Error message on the instrument cluster indicating exhaust system malfunction
• Engine hesitation or loss of hydraulic responsiveness during high-temperature operations

Potential Causes

Faulty Exhaust Temperature Sensor – The most common cause in used PC210-7s, typically from thermal cycling fatigue after 5,000+ hours of operation.

Damaged Wiring Harness – Heat-damaged or chafed wires near the DPF housing where the harness routes close to hot exhaust components, a known wear point on this model.

Corroded or Loose Connector Pins – The sensor connector exposed to moisture and heat cycles, particularly common in machines operated in humid or coastal environments.

ECM Internal Fault – Less common, but possible voltage regulator issues within the engine control module affecting the 5-volt reference circuit.

Short to Ground or Power – Wire insulation breakdown causing intermittent voltage spikes or drops in the sensor circuit.

How to Troubleshoot and Fix Code E246

Step 1: Visual Inspection Begin by locating the exhaust temperature sensor on the DPF outlet pipe. Inspect the sensor connector for corrosion, bent pins, or heat damage. On used excavators, check the wiring harness from the sensor to the ECM for signs of rubbing, melting, or rodent damage, particularly where it passes near the turbocharger and exhaust manifold.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure resistance across the sensor terminals. At room temperature (68°F/20°C), resistance should read approximately 100-150 ohms (refer to Komatsu service manual for exact specifications). Next, check for continuity in the harness wiring and verify no short to ground exists by testing between each wire and chassis ground (should read infinite resistance).

Step 3: Voltage Signal Verification With the ignition on and sensor connected, backprobe the signal wire at the ECM connector using a multimeter set to DC voltage. You should see approximately 0.5-1.2 volts at ambient temperature. If voltage reads 0 volts or 5+ volts, the sensor has failed. Use Komatsu diagnostic software (KOMTRAX or PC-based diagnostic tool) to monitor live sensor data and confirm the ECM is receiving proper signals.

Step 4: Component Replacement If testing confirms sensor failure, replace with a genuine Komatsu exhaust temperature sensor (Part #6261-E1-1710 or equivalent). For used machines, always apply high-temperature anti-seize compound to threads and use a new sensor gasket. After installation, clear the fault code using diagnostic software and perform a forced DPF regeneration to verify proper operation.

Important for Used Excavators: Before replacing the sensor, thoroughly inspect all harness routing and use high-temperature harness wrap on any sections showing wear. Many E246 codes on older PC210-7s stem from intermittent wiring issues rather than actual sensor failure.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and seek professional assistance from certified Komatsu technicians for complex repairs or if you're unfamiliar with electrical diagnostics.