What is Hitachi ZW310-5A Fault Code 111704-7?

Fault Code 111704-7 on the Hitachi ZW310-5A wheel loader indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to CAN bus data transmission errors or electrical system voltage irregularities. This code triggers when the machine's electronic control system detects inconsistent signal patterns between the engine ECM and other critical controllers, such as the hydraulic control unit or transmission controller.

This fault is particularly critical for the ZW310-5A because this model relies on integrated CAN bus communication to coordinate engine performance with hydraulic demand and transmission shifting. When communication fails, the machine cannot optimize fuel delivery, torque management, or implement hydraulic functions properly. For used excavators and wheel loaders, degraded wiring harnesses and corroded connectors are common culprits that trigger this specific diagnostic trouble code.

Common Symptoms

When Code 111704-7 is active, operators typically experience:

• Check Engine Warning Light illuminated on the instrument cluster, often accompanied by a diagnostic lamp
• Intermittent loss of power or sudden engine derate mode, limiting RPM to 1,500 or lower
• Erratic hydraulic response where boom, bucket, or steering functions respond sluggishly or unpredictably
• Transmission shift problems, including failure to shift gears or remaining stuck in low gear
• Multiple fault codes appearing simultaneously, indicating widespread communication failure across control modules

Potential Causes

The most common technical causes for Code 111704-7 on used Hitachi ZW310-5A machines include:

• CAN bus wiring harness damage from rubbing against frame components near the engine firewall or along the boom base pivot point
• Corroded or loose connector pins at the ECM multi-pin connector (C1 or C2), especially on machines operated in coastal or high-humidity environments
• Failing ECM internal circuitry due to voltage spikes or water intrusion through damaged seals
• Low battery voltage or poor ground connections at the main chassis ground points behind the cab
• Aftermarket electrical accessories improperly wired into the machine's electrical system, causing voltage drain or interference

How to Troubleshoot and Fix Code 111704-7

Step 1: Perform Visual Harness Inspection Begin by conducting a thorough inspection of the main engine harness from the ECM to the chassis connectors. On used ZW310-5A loaders, check the harness routing along the right side engine mount where vibration causes insulation wear. Look for chafing, exposed copper, or melted insulation. Use a digital multimeter to check for continuity between CAN-High and CAN-Low wires (typically 120-ohm resistance when measured across the bus).

Step 2: Check Electrical Connections and Voltage Supply Inspect the ECM connector (located behind the operator's seat panel). Remove connectors C1 and C2, then clean all pins with electrical contact cleaner. Check for bent pins or green corrosion. Verify battery voltage is between 24-28V (this is a 24V system) at the ECM power supply pins with the key on. Check the chassis ground strap from the engine block to the frame—corrosion here causes numerous electrical faults on older machines.

Step 3: Use Diagnostic Software for Advanced Testing Connect Hitachi Dr.EX diagnostic software or an equivalent J1939-compatible scan tool to the diagnostic port under the dash. Monitor live CAN bus communication traffic and baud rate (should be 250 kbps). If communication dropout is visible during engine operation, suspect ECM internal failure. For used excavators, also check software version—outdated ECM firmware on machines from 2012-2015 production years sometimes causes intermittent communication errors that require flashing updates.

Step 4: Inspect Aftermarket Modifications Many used machines have added accessories like GPS trackers, radios, or auxiliary lights. Verify these are properly fused and not tapping directly into ECM power circuits. Remove aftermarket components temporarily to see if the fault clears.

---

Disclaimer: This guide provides general troubleshooting information for educational purposes. Always consult the official Hitachi service manual for your specific machine serial number and consider having a certified Hitachi technician or qualified heavy equipment mechanic perform electrical diagnostics, as improper testing can damage sensitive electronic control modules.