What is Komatsu PC360-7 Fault Code DLE2MA?

Fault Code DLE2MA on the Komatsu PC360-7 indicates a communication error between the Engine Controller (ECM) and the Hydraulic Control Module (HCM). This diagnostic trouble code specifically signals that the Controller Area Network (CAN) data link is experiencing transmission failures or abnormal messaging between these two critical control units.

In the PC360-7's integrated control architecture, the ECM and HCM must constantly exchange operational data to coordinate engine power delivery with hydraulic demands. When this CAN bus communication breaks down, the machine cannot properly regulate engine speed relative to hydraulic load, potentially causing erratic operation or protective shutdowns. This code is particularly critical because it directly impacts the excavator's ability to optimize fuel efficiency and respond to operator inputs smoothly.

Common Symptoms

When DLE2MA is active on your PC360-7, operators typically experience:

• Intermittent loss of hydraulic power or sluggish boom/arm response despite normal engine RPM
• Monitor warning light illuminated on the instrument cluster, often accompanied by a service wrench icon
• Engine may run rough or fail to respond to throttle inputs during heavy hydraulic work cycles
• Automatic engine derate mode engaging unexpectedly, limiting maximum RPM to protect systems
• Complete machine shutdown in severe cases where the controllers cannot establish communication at startup

Potential Causes

The DLE2MA code on used PC360-7 excavators commonly stems from:

• Damaged CAN bus wiring harness between the ECM (located near the engine) and HCM (mounted in the cab area)—particularly at routing points near the swing bearing where harness flex occurs
• Corroded or loose connector terminals at either the ECM or HCM CAN-H and CAN-L pins, especially on machines operated in marine or high-moisture environments
• Failed terminating resistor on the CAN network (should measure 60 ohms across CAN-H to CAN-L)
• ECM or HCM internal failure—more common on machines with 8,000+ operating hours
• Voltage supply issues to either controller (should be stable 24V DC)

How to Troubleshoot and Fix Code DLE2MA

Step 1: Initial Verification and Voltage Check Using a multimeter, verify battery voltage at both the ECM and HCM connectors with the key in the ON position. You should measure 24V ± 1V DC. Check all ground connections for corrosion or looseness. Connect Komatsu KOMTRAX diagnostic software or a compatible scan tool to confirm the code is current and check for additional stored codes.

Step 2: CAN Bus Integrity Testing With the key OFF and both controllers disconnected, measure resistance between CAN-H and CAN-L terminals at the main harness connectors. The terminating resistor should give a reading of approximately 60 ohms. Inspect the entire wiring harness route from engine compartment to cab, paying special attention to areas where the harness passes through bulkheads or near moving components—used excavators frequently develop harness chafing at these wear points.

Step 3: Connector and Controller Diagnosis Thoroughly inspect all connector pins for bent contacts, corrosion (green oxidation), or moisture intrusion. On high-hour machines, apply dielectric grease after cleaning contacts with electrical contact cleaner. If wiring and connections test good, perform a controller isolation test: disconnect one controller at a time and attempt communication with the remaining unit. A failed ECM or HCM will need replacement with a Komatsu-programmed unit matched to your machine's serial number.

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu PC360-7 service manual and consider professional diagnostic assistance for complex electrical issues, especially when replacing controllers that require programming.