What is Komatsu PC200-7 Fault Code E115?

Fault Code E115 on the Komatsu PC200-7 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit with the pump controller or hydraulic system. Specifically, this code signals that the ECM has detected an abnormal signal or loss of communication between the engine control system and the hydraulic pump's electronic control unit. This communication failure prevents the excavator from properly coordinating engine output with hydraulic demand, which is critical for the PC200-7's integrated engine-hydraulic matching system that optimizes fuel efficiency and performance.

This fault is particularly significant in the PC200-7 model because Komatsu's CLSS (Closed-Center Load Sensing System) relies heavily on continuous data exchange between the engine ECM and pump controller to adjust hydraulic flow based on real-time operating conditions. When communication breaks down, the machine cannot perform this critical coordination function.

Common Symptoms

When Code E115 is active on your PC200-7, operators typically experience:

• Warning lamp illumination on the instrument panel, often accompanied by a diagnostic trouble code display
• Reduced hydraulic response or sluggish boom/arm/bucket movements despite normal engine RPM
• Engine derating or automatic reduction to low-idle mode as a protective measure
• Intermittent loss of power during combined functions (swing and lift operations)
• Erratic pump control resulting in inconsistent digging force or cycle times

Potential Causes

The most common technical reasons for E115 appearing on used PC200-7 excavators include:

• Corroded or damaged wiring harness between the ECM and pump controller, particularly at connector C201 near the pump mounting area where vibration and hydraulic oil mist cause deterioration
• Failed pump controller solenoid or internal circuit board damage due to age and thermal cycling
• ECM internal fault or corrupted memory affecting communication protocols
• Loose or oxidized ground connections at the main chassis ground points (common in machines with 5,000+ operating hours)
• Water intrusion into connector seals, especially on machines stored outdoors or operated in wet conditions
• Voltage supply issues from the main relay or battery system causing intermittent power to control modules

How to Troubleshoot and Fix Code E115

Step 1: Initial Diagnostic Connection Connect a Komatsu diagnostic tool (KDW or compatible scan tool) to the diagnostic port located under the right-side cab floor panel. Read and record all active and stored fault codes. Check freeze frame data to determine if E115 occurs during specific operating conditions or appears randomly.

Step 2: Visual and Physical Inspection Thoroughly inspect the main wiring harness running from the ECM (mounted behind the left console) to the hydraulic pump area. On used PC200-7 models, pay special attention to the harness routing near the swing bearing and along the upper structure frame where rubbing against metal edges is common. Check connector C201 (pump controller connector) and C107 (ECM engine harness) for corrosion, bent pins, or moisture. Clean connectors with electrical contact cleaner and apply dielectric grease.

Step 3: Electrical Testing Using a digital multimeter, verify power supply voltage at the pump controller. You should read 24V DC (±2V) at the power supply pin with the key switch on. Check ground continuity between the pump controller case and battery negative—resistance should be less than 1 ohm. Inspect the CAN bus communication lines (typically a twisted pair) for proper voltage levels: approximately 2.5V on each wire with key on, engine off.

Step 4: Component Testing If wiring checks pass, test the pump controller solenoid resistance. Disconnect the harness and measure resistance across solenoid terminals—typical specification is 20-40 ohms at room temperature. Out-of-range readings indicate internal coil failure. For used excavators with over 8,000 hours, consider that the pump controller's internal circuits may have deteriorated even if resistance checks pass.

Step 5: Advanced Diagnostics If previous steps don't identify the problem, monitor real-time communication data using Komatsu diagnostic software. Watch for communication timeouts or error frames on the CAN network. A failing ECM will show irregular message transmission patterns. Before replacing the ECM (an expensive component on used machines), verify that the machine's software version is current, as outdated firmware can cause communication protocol mismatches.

Critical Note for Used Excavators: Before purchasing expensive replacement parts, thoroughly clean all connectors and check for harness chafing at known wear points. Many E115 codes on high-hour machines resolve after addressing corroded connections rather than component replacement.

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Disclaimer: This guide provides general technical information for diagnostic purposes. Always consult the official Komatsu service manual for your specific serial number and consider professional assistance from a certified Komatsu technician for complex electrical diagnostics and repairs.