What is Komatsu PC210LC-10 Fault Code L01CA698?

Fault Code L01CA698 indicates a communication error between the Engine Control Module (ECM) and the Pump Control Unit (PCU) on the Komatsu PC210LC-10 excavator. This diagnostic trouble code specifically signals that the CAN (Controller Area Network) bus communication has been interrupted or degraded between these two critical control systems.

The PC210LC-10 relies on seamless digital communication between the ECM and PCU to optimize engine performance with hydraulic demand. The ECM manages engine speed and torque output, while the PCU controls hydraulic pump displacement to match workload requirements. When this communication link fails, the machine cannot properly coordinate power delivery with hydraulic flow, resulting in inefficient operation and potential component stress. This code is particularly critical because it affects the CLSS (Closed-Center Load-Sensing System), which is fundamental to this excavator's fuel efficiency and productivity.

Common Symptoms

• Warning light activation on the monitor panel, typically displaying "Check Engine" or a wrench icon with reduced machine responsiveness
• Degraded hydraulic performance, including slower cycle times, reduced digging force, or inconsistent swing speed
• Engine derating where the ECM limits RPM to protect components, preventing the machine from reaching full power
• Intermittent loss of power modes, with the excavator randomly switching between economy and power modes without operator input
• Communication error messages displayed on the multi-function monitor, sometimes accompanied by complete loss of monitor functions

Potential Causes

The most common technical failures triggering L01CA698 on used PC210LC-10 excavators include:

• CAN bus harness damage at known wear points, particularly where the wiring passes through the cab riser near the hydraulic valve bank—vibration and rubbing create exposed wires
• Corroded or loose connectors on either the ECM (located behind the operator seat) or PCU (mounted on the hydraulic pump), especially on machines operated in coastal or high-humidity environments
• Failed termination resistors within the CAN network causing signal reflection and data corruption
• ECM or PCU internal failure, though less common, voltage spikes from faulty alternators or jump-starting errors can damage controller circuits
• Grounding issues where paint buildup or rust on mounting points creates electrical resistance in the chassis ground path

How to Troubleshoot and Fix Code L01CA698

Step 1: Visual Harness Inspection Begin by physically inspecting the CAN communication harness from the ECM to the PCU. On used excavators, focus on the wiring bundle routing through the cab riser assembly and around the hydraulic pump mounting area. Look for abrasion marks, exposed copper wire, or melted insulation. Check all connector boots for cracks where moisture could enter.

Step 2: Connector and Ground Verification Disconnect the 22-pin ECM connector and 18-pin PCU connector. Inspect pins for corrosion (green/white deposits), bent terminals, or pushed-back pins. Clean contacts with electrical contact cleaner. Using a digital multimeter, verify chassis ground integrity by measuring resistance from ECM mounting bolt to battery negative—readings above 0.5 ohms indicate poor grounding requiring wire brushing of contact surfaces.

Step 3: CAN Bus Signal Testing With Komatsu KOMTRAX diagnostic software or compatible scan tool, monitor live CAN bus voltage while wiggling harnesses. Proper CAN-High should read 2.5-3.5V and CAN-Low 1.5-2.5V at idle. Measure termination resistance across CAN-High and CAN-Low pins (typically terminals 6 and 14 on ECM connector)—should read approximately 60 ohms with both controllers connected. Readings outside 55-65 ohms suggest failed termination resistor or open circuit.

Step 4: Component Isolation If harness and grounds test properly, disconnect the PCU and measure ECM CAN output directly. Erratic voltage or inability to communicate with scan tool points to ECM failure. If ECM communicates normally when PCU is disconnected, the Pump Control Unit likely requires replacement. For used excavators, always verify the replacement PCU software version matches machine specifications, as mismatched firmware causes ongoing communication faults.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu PC210LC-10 service manual and follow lockout/tagout procedures. Improper diagnosis can cause expensive component damage. When working on used equipment with unknown repair history, professional diagnostic assistance is recommended to avoid replacing functional parts.