What is Hitachi ZX210LC-5G-HCMC Fault Code 11402-2?

Fault Code 11402-2 indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically a voltage abnormality or signal interruption in the CAN (Controller Area Network) data line. This code triggers when the excavator's ECM detects inconsistent or absent communication signals between critical control modules, preventing proper coordination between the engine management system and hydraulic controls.

On the Hitachi ZX210LC-5G-HCMC, this fault affects the integrated control system that manages engine performance, fuel injection timing, and hydraulic pump output. The CAN bus network is the central nervous system of modern excavators, and any disruption can cause multiple operational issues. This code is particularly critical because it can lead to engine derating, reduced hydraulic response, and potential safety system failures. In used machines, degraded wiring harnesses and corroded connectors are common culprits that trigger this communication error.

Common Symptoms

• Engine warning light illuminated on the instrument panel with possible engine derate mode engaged
• Erratic hydraulic performance, including inconsistent boom or arm speed responses
• Intermittent engine stalling or rough idling, especially during cold starts
• Loss of communication with diagnostic tools or inability to read other system parameters
• Reduced engine power output (limp mode) limiting machine productivity to 60-70% capacity

Potential Causes

The most frequent causes of Code 11402-2 on used ZX210LC-5G-HCMC excavators include:

• Damaged or corroded CAN bus wiring harness, particularly at flex points near the engine mount or along the chassis where cable routing experiences vibration and movement
• Faulty ECM ground connections or corroded ground terminals causing voltage irregularities in the communication circuit
• Water intrusion into the main harness connectors (common in excavators operating in wet conditions or those with compromised cable glands)
• Failed termination resistors on the CAN network endpoints (typically 120-ohm resistors that maintain signal integrity)
• ECM internal failure or corrupted software, though less common than harness-related issues in used equipment

How to Troubleshoot and Fix Code 11402-2

Step 1: Visual Harness Inspection Begin by thoroughly inspecting the main wiring harness from the ECM to all connected modules. On used excavators, focus on areas where the harness passes through bulkheads, near the engine mounting points, and along the undercarriage where abrasion occurs. Look for chafed insulation, pinched wires, or evidence of rodent damage. Check all connector pins for corrosion, bent terminals, or moisture intrusion—clean with electrical contact cleaner and dielectric grease if necessary.

Step 2: CAN Bus Voltage and Resistance Testing Using a digital multimeter, measure the resistance between CAN-High and CAN-Low terminals at the ECM connector (engine off). You should read approximately 60 ohms with both termination resistors in place. Next, with the key on (engine off), measure voltage on the CAN lines—expect around 2.5V on each line at rest. Significant deviation indicates a short circuit, open circuit, or failed termination resistor. For used machines, verify all ground points show less than 0.5 ohms resistance to chassis ground.

Step 3: ECM Power Supply and Software Verification Confirm the ECM receives proper battery voltage (12-14V) and clean ground. Test the ignition switch circuit to ensure stable power during cranking. Connect Hitachi Dr.EX diagnostic software (or equivalent professional scan tool) to check for additional fault codes and verify ECM software version. On older used excavators, outdated firmware can cause communication glitches—consult with a Hitachi dealer about available software updates. If all wiring and power checks pass, the ECM itself may require replacement or professional bench testing.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific machine serial number and consider professional diagnostic assistance for complex electrical issues, especially when dealing with ECM replacement or CAN bus network repairs.