Komatsu PC220-7 Fault Code E-19: Technical Guide

What is Komatsu PC220-7 Fault Code E-19?

Komatsu PC220-7 Fault Code E-19 indicates a malfunction in the hydraulic pump pressure sensor circuit, specifically detecting an abnormal voltage signal from the main pump pressure sensor to the controller. This code is triggered when the Engine Control Module (ECM) receives voltage readings outside the acceptable range (typically below 0.5V or above 4.5V) from the pressure sensor that monitors hydraulic pump output.

This fault is critical for the PC220-7 because the hydraulic pump pressure sensor directly influences the machine's load-sensing system. When this sensor fails or sends incorrect signals, the ECM cannot properly regulate pump output, leading to reduced hydraulic performance and potential component damage. For used excavators, this code often indicates sensor degradation or wiring harness issues common in machines with 5,000+ operating hours.

Common Symptoms

• Hydraulic system operates sluggishly with noticeably reduced swing speed, arm movement, or bucket breakout force
• Intermittent or constant warning lamp illumination on the monitor panel (typically amber)
• Engine RPM fluctuations during loaded operations as the ECM attempts to compensate for incorrect pressure readings
• Erratic attachment response, particularly when performing multiple simultaneous functions (e.g., boom lift while rotating)
• Machine enters derate mode in severe cases, limiting engine power to protect the hydraulic system

Potential Causes

Faulty hydraulic pump pressure sensor – The most common failure point, especially in used machines where sensor diaphragms deteriorate or internal electronics fail from vibration and heat exposure.

Damaged or corroded wiring harness – The sensor harness runs along the main pump housing where it's exposed to hydraulic fluid mist, heat, and physical contact. On PC220-7 models, check for wire chafing near the pump mounting bracket.

Corroded or loose connector pins – The 3-pin sensor connector accumulates moisture and contaminants, creating high resistance or intermittent connections.

ECM calibration drift or software issues – Less common but possible in machines with voltage irregularities or previous electrical system repairs.

Contaminated hydraulic oil affecting sensor operation – Metal particles or water in the hydraulic system can damage the sensor's pressure port.

How to Troubleshoot and Fix Code E-19

Step 1: Visual Inspection and Connection Check Begin by locating the hydraulic pump pressure sensor on the main pump body (driver's side, near the regulator). Inspect the wiring harness for obvious damage, particularly where it contacts the pump housing or frame rails—a known rub point on used PC220-7 machines. Disconnect the 3-pin connector and examine pins for corrosion, bent terminals, or hydraulic oil contamination. Clean with electrical contact cleaner and apply dielectric grease before reconnecting.

Step 2: Sensor Voltage and Resistance Testing Using a digital multimeter, check sensor power supply with the ignition on (engine off). You should read approximately 5 volts on the power pin (refer to Komatsu service manual for exact pin configuration). Test sensor output voltage while monitoring with Komatsu diagnostic software (KOMTRAX) or an aftermarket scan tool—normal readings range from 0.5V at low pressure to 4.5V at maximum system pressure. Check sensor ground continuity to the ECM; resistance should be less than 5 ohms.

Step 3: Sensor Replacement and System Verification If voltage readings are erratic or out of specification, replace the pressure sensor (Komatsu part number 7861-93-1650 or equivalent). On used excavators, simultaneously inspect the hydraulic filter and oil condition—contamination often accelerates sensor failure. After replacement, clear fault codes using diagnostic software, cycle the machine through all hydraulic functions, and verify code does not return. If E-19 persists after sensor replacement, suspect ECM issues or internal pump wear affecting actual pressure regulation.

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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 consider professional diagnostic assistance for complex electrical or hydraulic system repairs. Improper repairs may void warranties or create safety hazards.