Komatsu PC200LC-8 Fault Code B@HANS: Complete Diagnostic Guide

What is Komatsu PC200LC-8 Fault Code B@HANS?

Fault Code B@HANS indicates a communication error or data transmission failure within the Komatsu PC200LC-8's CAN (Controller Area Network) bus system, specifically related to the hydraulic attachment control system or auxiliary hydraulic circuit monitoring.

This code appears when the machine's Electronic Control Module (ECM) cannot properly communicate with sensors or controllers managing auxiliary hydraulic functions. The PC200LC-8 uses sophisticated CAN bus protocols to coordinate multiple systems, and B@HANS signals a breakdown in this critical communication network. This fault is particularly important because it can affect attachment performance, hydraulic response times, and overall machine efficiency—issues that significantly impact productivity on job sites.

Common Symptoms

When fault code B@HANS is active, operators typically experience:

• Intermittent or complete loss of auxiliary hydraulic functions (breakers, thumbs, grapples may not respond)
• Illuminated warning lamp on the instrument cluster, often accompanied by error messages on the monitor panel
• Erratic hydraulic attachment behavior, including delayed response or unexpected shutoff during operation
• Reduced hydraulic flow to attachments even when main hydraulics function normally
• Error messages on the Komtrax monitor indicating communication failures

Potential Causes

The most common technical causes for B@HANS on used PC200LC-8 excavators include:

• Damaged or corroded wiring harness between the main ECM and auxiliary hydraulic control solenoids (common wear point near the boom cylinder)
• Failed CAN bus termination resistors causing signal reflection and communication errors
• Faulty auxiliary hydraulic pressure sensor sending incorrect or no data to the ECM
• Corroded or loose connectors at the attachment control valve, especially on machines operating in wet or corrosive environments
• ECM software glitches requiring recalibration or updates (particularly on earlier production year models)
• Grounding issues at chassis ground points, which deteriorate on used machines from rust and vibration

How to Troubleshoot and Fix Code B@HANS

Step 1: Visual Inspection Begin by inspecting the wiring harness running from the cab to the auxiliary hydraulic control valve. On used excavators, check for harness rubbing against the boom cylinder or structural components—a known wear point on PC200LC-8 models. Examine all electrical connectors for corrosion, bent pins, or moisture intrusion.

Step 2: CAN Bus Resistance Check Using a digital multimeter, disconnect the battery and measure resistance across the CAN-H and CAN-L lines at the auxiliary control module connector. You should read approximately 60 ohms with proper termination. Readings significantly higher suggest open circuits or failed termination resistors.

Step 3: Sensor and Solenoid Testing Test the auxiliary hydraulic pressure sensor voltage output (typically 0.5-4.5V depending on pressure). Check solenoid valve resistance (usually 10-30 ohms depending on valve type). Replace sensors showing out-of-spec readings.

Step 4: Diagnostic Software Scan Connect Komatsu diagnostic software (KTEC or equivalent) to read detailed fault parameters. Check for additional stored codes that may indicate the root cause. Clear codes and monitor for recurrence during hydraulic function tests.

Step 5: Ground Point Verification Inspect and clean all chassis ground points, particularly G101 and G102 near the hydraulic pump. On used machines, corrosion here frequently causes intermittent communication errors.

For used excavators, prioritize inspecting harness friction points and connector integrity before replacing expensive components like control modules or sensors.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific serial number and seek professional diagnostic assistance for complex electrical issues.