Komatsu PC210LC-10 Fault Code DHSJMA: Complete Diagnostic Guide

What is Komatsu PC210LC-10 Fault Code DHSJMA?

Fault Code DHSJMA on the Komatsu PC210LC-10 indicates a communication error between the machine's Engine Control Module (ECM) and the Hydraulic System Controller, specifically related to data transmission failure in the CAN bus network. This code triggers when the Controller Area Network (CAN) experiences signal interruption or degraded communication between critical control units.

This fault is particularly critical for the PC210LC-10 because this model relies on integrated electronic control for coordinating engine performance with hydraulic demand. When communication breaks down, the excavator's automatic power mode and fuel efficiency systems cannot function properly, potentially leading to reduced productivity and increased fuel consumption. The PC210LC-10's advanced monitoring system depends on constant data flow between controllers to optimize digging force and swing speed.

Common Symptoms

When DHSJMA is active on your PC210LC-10, operators typically experience:

• Warning light illumination on the monitor panel with simultaneous error message display
• Loss of auto-idle function and inability to switch between power modes (S/H/P modes)
• Erratic hydraulic response or reduced digging force despite proper throttle input
• Intermittent gauge failures including fuel level, coolant temperature, or hydraulic oil temperature readings
• Engine derate mode limiting RPM to approximately 1,500-1,800 range in severe cases

Potential Causes

The most common technical reasons for DHSJMA on used PC210LC-10 excavators include:

• CAN bus harness damage at known wear points near the swing bearing and along the boom base where cables flex repeatedly
• Corroded connector pins in the main wiring harness junction box (located behind the operator cab)
• Failed termination resistor in the CAN network causing signal reflection
• ECM or hydraulic controller internal failure due to moisture intrusion or age-related component degradation
• Voltage supply issues from deteriorated ground connections specific to controller modules
• Aftermarket component interference from non-OEM monitors or third-party telematics devices improperly spliced into the network

How to Troubleshoot and Fix Code DHSJMA

Step 1: Initial Inspection and Code Reading Connect Komatsu KOMPCS diagnostic software or a compatible CAN bus scanner to the diagnostic port under the operator seat. Record all active and stored fault codes. Check battery voltage—it must maintain 24V minimum (for dual 12V system) during cranking.

Step 2: Physical Harness Examination Inspect the main wiring harness from the ECM (located under the right-side engine cover) to the hydraulic controller (mounted near the hydraulic pump). Focus on areas where harnesses pass through the swing bearing and along structural edges. Look for chafing, cracking, or exposed wires. On used excavators, pay special attention to the waterproof boots at connectors—deteriorated seals allow corrosion.

Step 3: Connector and Resistance Testing Disconnect the 6-pin CAN connector at both the ECM and hydraulic controller. Inspect pins for green corrosion or bent contacts. Using a digital multimeter, measure resistance between CAN-High and CAN-Low terminals—you should read approximately 60 ohms with both controllers disconnected (indicating proper termination resistors). Any reading above 100 ohms or below 40 ohms indicates termination resistor failure.

Step 4: Ground Circuit Verification Test ground integrity at G301 (engine block ground) and G401 (frame ground near battery box). Resistance to battery negative should be less than 0.5 ohms. Clean and retighten all ground connections—corrosion at ground points is extremely common in excavators operating in wet conditions.

Step 5: Controller Power Supply Check With ignition ON, verify that both controllers receive proper voltage. ECM should show 23-26V at power supply pin. Low voltage often indicates issues with the ignition relay or deteriorated power distribution cables specific to used machines.

Critical Note for Used Excavators: Before replacing expensive controllers, thoroughly inspect all harness routing for previous repair attempts. Check for electrical tape repairs or wire splices that may create intermittent connections. Verify that no aftermarket devices are improperly connected to the CAN network.

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Disclaimer: This guide provides general troubleshooting procedures for experienced diesel mechanics. Complex electrical diagnostics on Komatsu equipment should be performed by technicians with proper training and access to manufacturer service literature. Always consult the PC210LC-10 Shop Manual (SEBM04260) for model-specific specifications and safety procedures before performing repairs.