What is Komatsu PC110-8M0 Fault Code E-6?

Fault Code E-6 on the Komatsu PC110-8M0 indicates a malfunction in the engine oil pressure sensor circuit or abnormally low engine oil pressure. This code is triggered when the Electronic Control Module (ECM) detects either an electrical fault in the oil pressure sensor wiring or an actual loss of proper oil pressure in the lubrication system.

On the PC110-8M0, proper engine oil pressure is critical for lubricating vital internal engine components, hydraulic pump drive systems, and preventing catastrophic engine failure. The oil pressure sensor sends real-time voltage signals to the ECM, which monitors pressure levels continuously during operation. When pressure falls below the manufacturer's threshold (typically around 1.0-1.5 kg/cm² at idle), or the sensor circuit shows open/short conditions, Code E-6 activates immediately to protect the engine from severe damage.

Common Symptoms

When Code E-6 is active on your Komatsu PC110-8M0, you may experience:

• Oil pressure warning light illuminated on the instrument panel (red oil can icon)
• Engine automatic shutdown or refusal to start as a protective measure
• Audible warning alarm sounding continuously in the cab
• Engine power derate or limited RPM range if the machine continues running
• Intermittent code activation during warm-up or under heavy load conditions

Potential Causes

The most common technical causes for Code E-6 on used PC110-8M0 excavators include:

• Failed oil pressure sensor due to internal diaphragm wear or contamination (common after 3,000+ hours)
• Low engine oil level or severely degraded oil viscosity from extended service intervals
• Damaged sensor wiring harness from rubbing against engine block near the oil filter mounting area (known wear point on this model)
• Corroded or loose electrical connectors at the sensor or ECM interface
• Worn oil pump or clogged oil pickup screen reducing actual system pressure
• ECM calibration issues or software glitches requiring parameter reset
• Faulty oil pressure relief valve stuck in open position

How to Troubleshoot and Fix Code E-6

Step 1: Verify Actual Oil Condition Before electrical diagnosis, check the engine oil level using the dipstick with the machine on level ground. Inspect oil quality—milky appearance indicates coolant contamination, while metallic particles suggest internal engine wear. On used excavators, ensure oil hasn't exceeded 500-hour service intervals, which can cause sensor fouling.

Step 2: Inspect Sensor and Wiring Locate the oil pressure sensor on the lower right side of the engine block near the oil filter. Using a digital multimeter, check for continuity in the sensor harness (typically a 3-wire connector: signal, ground, 5V reference). Inspect for corroded pins, frayed wires, or harness damage from rubbing—a critical check point on PC110 models where the harness routes close to the alternator bracket.

Step 3: Test Sensor Output With ignition ON but engine OFF, measure sensor signal voltage at the ECM connector (should read approximately 0.5-1.0V). During cranking or idle, voltage should increase to 2.5-4.5V depending on actual pressure. Compare readings against Komatsu specifications using KOMTRAX diagnostic software or compatible scan tool.

Step 4: Verify Mechanical Oil Pressure Install a mechanical oil pressure gauge into the sensor port. Start the engine and confirm actual pressure meets specifications (typically 3.5-5.0 kg/cm² at 2,000 RPM). Low readings indicate worn oil pump, clogged filter, or bearing clearance issues requiring mechanical repair.

Step 5: Component Replacement If sensor testing shows out-of-range values but mechanical pressure is adequate, replace the oil pressure sensor (Komatsu part number specific to PC110-8M0). For used machines, also replace the connector pigtail if corrosion is evident. Clear codes using diagnostic software and perform operational test.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu PC110-8M0 service manual and consider professional evaluation for complex repairs or if unfamiliar with electrical systems.