Komatsu PC200LC-8 Fault Code E15 CA2555: Technical Guide

What is Komatsu PC200LC-8 Fault Code E15 CA2555?

Fault Code E15 CA2555 indicates a communication error between the Engine Controller (ECM) and the Pump Controller in the Komatsu PC200LC-8 excavator. This code specifically relates to a CAN (Controller Area Network) bus communication failure affecting the hydraulic system's ability to receive proper engine load data.

This fault directly impacts the pump flow control system, which relies on continuous data exchange between controllers to optimize hydraulic performance and fuel efficiency. The PC200LC-8 uses Komatsu's CLSS (Closed-Center Load Sensing System), making this communication link critical for proper machine operation. When this communication breaks down, the excavator cannot properly match hydraulic pump output to engine speed and load conditions.

Common Symptoms

When Code E15 CA2555 is active, operators typically experience:

• Warning light illumination on the instrument cluster with reduced hydraulic response
• Sluggish hydraulic movements across all functions (boom, arm, bucket, swing)
• Engine derating or inability to reach full RPM under load
• Erratic pump behavior with inconsistent flow rates during operation
• Intermittent fault activation, especially when operating in wet conditions or over rough terrain

Potential Causes

The most common technical causes for this fault code include:

• CAN bus wiring damage between ECM and Pump Controller, particularly at harness routing points near the swing motor where vibration and flexing occur
• Corroded or loose connector pins at the X2 connector on the Pump Controller (common in machines operating in wet/muddy environments)
• Failed Pump Controller module due to water intrusion or age-related component failure
• ECM grounding issues causing voltage fluctuations on the communication network
• Damaged termination resistors on the CAN network (120-ohm resistors at network endpoints)
• Previous repair attempts using non-OEM harnesses with incorrect wire gauge or shielding

How to Troubleshoot and Fix Code E15 CA2555

Step 1: Visual Inspection Begin with a thorough inspection of all wiring harnesses between the engine compartment and pump controller. On used PC200LC-8 excavators, check the harness routing near the swing bearing and along the main chassis rail where abrasion commonly occurs. Look for pinched wires, worn insulation, or evidence of previous repairs.

Step 2: Connector Examination Disconnect and inspect the X2 connector at the Pump Controller (located under the operator's cab, right side). Clean all pins with electrical contact cleaner and check for green corrosion, bent pins, or moisture inside the connector body. This is the most common failure point in machines over 5,000 hours.

Step 3: CAN Bus Continuity Testing Using a digital multimeter, measure resistance between CAN-High and CAN-Low pins at both the ECM and Pump Controller connectors (consult service manual for exact pin locations). You should read approximately 60 ohms with both controllers disconnected, indicating proper termination resistors. Infinite resistance suggests an open circuit in the harness.

Step 4: Voltage Testing With ignition on (engine off), verify battery voltage (12V nominal) is present at the Pump Controller power supply pins. Check for voltage drops exceeding 0.5V, which indicate poor ground connections or corroded power supply wiring.

Step 5: Diagnostic Software Analysis Connect Komatsu KOMTRAX or authorized diagnostic software to read real-time CAN bus traffic. Monitor for communication dropouts or error frames that pinpoint whether the ECM or Pump Controller is failing to transmit. This step requires genuine diagnostic tools for accurate results.

Step 6: Component Replacement If harness and connections test properly, the Pump Controller itself may require replacement. On used excavators, verify the replacement part number matches your machine's serial number range, as Komatsu made mid-production updates to controller firmware.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and consider professional diagnosis for complex electrical issues. Improper repairs can cause additional system damage.