What is Komatsu PC110-8M0 Fault Code E-32?

Fault Code E-32 on the Komatsu PC110-8M0 indicates a Hydraulic Pump Solenoid Valve Circuit Malfunction, specifically related to the main pump's electronic control system. This code triggers when the Electronic Control Module (ECM) detects an abnormal voltage or current reading in the circuit that controls the hydraulic pump's displacement solenoid valve.

This diagnostic trouble code is critical for the PC110-8M0 because the proportional solenoid valve regulates hydraulic pump output based on operator demand and load conditions. When this circuit malfunctions, the excavator loses its ability to optimize hydraulic flow, directly impacting digging force, swing speed, and overall machine productivity. For used excavators, this code often indicates age-related electrical issues rather than catastrophic pump failure.

Common Symptoms

Operators experiencing E-32 typically notice:

• Reduced hydraulic power across all functions, with noticeably slower cycle times
• Intermittent or constant warning lamp illumination on the monitor panel
• Erratic boom, arm, or bucket response that doesn't match joystick input
• Engine operating normally but hydraulic functions feeling "lazy" or unresponsive
• Possible automatic derate mode limiting engine RPM to protect the hydraulic system

Potential Causes

The most common technical causes for E-32 on used PC110-8M0 excavators include:

• Damaged wiring harness near the main pump mounting area where vibration causes insulation wear
• Corroded or loose connector pins at the solenoid valve plug (18-pin connector)
• Failed proportional solenoid valve coil due to internal short or open circuit
• ECM power supply issues affecting the 12V output to solenoid circuits
• Moisture intrusion into connectors from damaged harness boots (common on older machines)
• Worn harness rub points where cables contact the pump housing or chassis frame

How to Troubleshoot and Fix Code E-32

Step 1: Visual Inspection Begin by inspecting the wiring harness running from the ECM to the hydraulic pump solenoid valve. On used excavators, check specifically where the harness passes near sharp edges or rotating components. Look for abraded insulation, cracked connector boots, or oil contamination that can cause shorts.

Step 2: Connector and Resistance Testing Disconnect the solenoid valve connector at the pump. Using a digital multimeter, measure resistance across the solenoid coil terminals—typical specification is 8-12 ohms. Also inspect connector pins for corrosion (green/white residue) and bent terminals. Clean contacts with electrical contact cleaner and dielectric grease.

Step 3: Voltage Supply Check With the ignition on (engine off), backprobe the connector to verify the ECM is supplying 12V to the solenoid circuit. Use Komatsu diagnostic software (KOMTRAX Plus or equivalent) to command the solenoid while monitoring voltage. Fluctuating voltage suggests harness damage between ECM and pump.

Step 4: Component Replacement Hierarchy For used machines, replace components in this cost-effective order: first the wiring harness (if damage found), then the solenoid valve itself, and finally consider ECM issues only after eliminating all field wiring problems. Always verify repairs by clearing codes and operating under load for 30+ minutes.

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