What is Komatsu PC210-8 Fault Code DXE6KB?

Komatsu PC210-8 fault code DXE6KB indicates a communication error between the Engine Controller (ECM) and the Hydraulic Controller (HMC). This code specifically identifies a CAN-bus data link failure or abnormal signal transmission within the machine's integrated control network.

The PC210-8 uses a sophisticated electronic architecture where the ECM (engine management) and HMC (hydraulic pump control) must constantly exchange data to optimize performance and fuel efficiency. When code DXE6KB triggers, the controllers cannot coordinate functions like auto-deceleration, combined mode operation, or pump flow adjustments. For used excavators, this fault is critical because it can force the machine into a safety derate mode, limiting productivity and potentially indicating deeper electrical degradation common in aging equipment.

Common Symptoms

• Warning light illuminated on the instrument panel (typically a wrench or system error icon)
• Loss of power management modes – machine may not respond to work mode selector (SP/H/S modes)
• Engine over-revving or stalling during combined operations (swing and boom movements)
• Erratic hydraulic response or inability to perform simultaneous functions smoothly
• Excessive fuel consumption due to loss of automatic engine-pump matching

Potential Causes

The DXE6KB code typically results from:

• CAN-bus wiring harness damage – particularly at rubbing points near the turret rotation area or along the engine bay where vibration and heat deteriorate insulation
• Corroded or loose connectors on the ECM or HMC modules (common in machines with 5,000+ operating hours)
• Failed termination resistors on the CAN network (120-ohm resistors at network endpoints)
• ECM or HMC controller failure – internal circuit degradation in controllers from older used machines
• Voltage supply issues – low battery voltage (below 22V on 24V systems) or failing alternator affecting controller stability
• Aftermarket modifications or improperly installed accessories disrupting CAN communications

How to Troubleshoot and Fix Code DXE6KB

Step 1: Verify Power Supply and Battery Condition Using a multimeter, check battery voltage with the engine off (should read 24-26V) and running (27-29V). Low voltage frequently causes false CAN-bus errors on used excavators. Inspect all ground connections at the battery, ECM, and HMC for corrosion.

Step 2: Inspect CAN-Bus Wiring Harness Physically trace the CAN-bus harness (typically twisted orange/blue pair) from the ECM (located near the engine) to the HMC (mounted under the operator cab). Focus on areas where harnesses pass through bulkheads or near moving components. Look for chafed insulation, crushed wires, or melted sections. On used machines, check for previous repair attempts with electrical tape rather than proper connectors.

Step 3: Test CAN Network Resistance Disconnect the CAN-bus connectors at both the ECM and HMC. Measure resistance between CAN-High and CAN-Low pins – you should read approximately 60 ohms (two 120-ohm termination resistors in parallel). Readings significantly different indicate failed resistors or open circuits.

Step 4: Check Controller Connectors Remove and inspect the multi-pin connectors at both controllers. Clean any corrosion with electrical contact cleaner. For used excavators with high hours, connector pin tension often weakens – inspect for pushed-back pins or discoloration indicating heat from poor connections.

Step 5: Use Diagnostic Software Connect Komatsu KOMTRAX or compatible diagnostic software. Monitor live CAN-bus communication status while wiggling harnesses to identify intermittent faults. Check for additional stored codes that might point to a specific controller failure.

Disclaimer: This guide provides general troubleshooting steps for experienced technicians. Always consult the official Komatsu service manual for your specific machine serial number. If you're uncomfortable with electrical diagnostics or the fault persists, contact a certified Komatsu technician to prevent further damage to expensive electronic components.