Komatsu PC110-8M0 Fault Code E-22: Complete Diagnostic Guide

What is Komatsu PC110-8M0 Fault Code E-22?

Fault Code E-22 on the Komatsu PC110-8M0 indicates a malfunction in the hydraulic oil temperature sensor circuit. This code triggers when the Engine Control Module (ECM) detects abnormal voltage readings from the temperature sensor monitoring hydraulic fluid in the main circuit.

The hydraulic oil temperature sensor plays a critical role in protecting the PC110-8M0's hydraulic system. When oil temperatures exceed safe operating limits (typically above 100°C/212°F), the sensor signals the ECM to activate warning protocols. For used excavators, this sensor's accuracy becomes increasingly important as aging seals and pumps generate more heat. Ignoring E-22 can lead to accelerated component wear, seal degradation, and catastrophic hydraulic pump failure.

Common Symptoms

When Code E-22 is active, operators typically experience:

• Hydraulic temperature warning light illuminated on the instrument cluster (amber or red)
• Reduced hydraulic responsiveness or sluggish arm/bucket movements as the system enters derate mode
• Intermittent code appearance that correlates with specific operations (often during high-demand cycles)
• Audible alarm or buzzer activation in the cab
• Hydraulic oil appearing darker or having a burnt odor due to actual overheating

Potential Causes

The most common technical causes for E-22 on used PC110-8M0 excavators include:

• Failed hydraulic oil temperature sensor (thermistor resistance out of specification, typically 2,000-3,000 ohms at 20°C)
• Damaged or corroded wiring harness between sensor and ECM, particularly at connector pins
• Chafed wiring near the hydraulic tank mounting bracket (known rub point on this model)
• Contaminated or deteriorated connector terminals exposing circuits to moisture
• ECM internal fault (rare, but possible in high-hour used machines)
• Actual hydraulic overheating due to clogged cooler, low oil level, or failing hydraulic pump

How to Troubleshoot and Fix Code E-22

Step 1: Visual Inspection Begin by inspecting the hydraulic oil temperature sensor located on the hydraulic tank's side panel. Check connector integrity for corrosion, bent pins, or oil contamination. On used excavators, examine the entire wiring harness from sensor to ECM for wear points, especially where harness contacts frame members.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across its terminals. At 20°C (68°F), resistance should read approximately 2,200-2,800 ohms. Compare readings against Komatsu's specification chart. Check continuity through the harness wiring (should read less than 5 ohms) and verify no short to ground (should read infinite resistance).

Step 3: Sensor Replacement and Verification If sensor readings are abnormal, replace with a genuine Komatsu temperature sensor (Part #: 7861-93-3320 or equivalent). Apply dielectric grease to connector pins to prevent future corrosion. Clear codes using Komatsu diagnostic software (KOMTRAX) or compatible scan tool. Operate machine through heat cycles and monitor for code recurrence.

Step 4: Address Root Causes in Used Equipment For older PC110-8M0 machines, inspect hydraulic oil cooler for debris buildup, verify hydraulic oil level and condition, and check for hydraulic system inefficiencies causing genuine overheating. Address these issues to prevent premature sensor failure.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific serial number and seek qualified technician assistance for complex repairs. Hydraulic systems operate under extreme pressure—improper procedures can cause injury.