What is Komatsu PC210-8 Fault Code E-22?

Fault Code E-22 on the Komatsu PC210-8 excavator indicates a malfunction in the Swing Motor Control System, specifically an abnormality detected in the swing motor solenoid valve circuit or its control signal from the machine's Controller (KMC). This code triggers when the electrical current or voltage supplied to the swing motor's proportional control solenoid falls outside the manufacturer's specified parameters, typically 0.5-4.5 volts DC.

The swing motor system is critical for the PC210-8's upper structure rotation functionality. When the KMC (Komatsu Machine Controller) detects irregular electrical feedback from the swing motor solenoid valve, it logs E-22 to prevent potential damage to hydraulic components and ensure operator safety. In used excavators, this fault often stems from deteriorated wiring harnesses or corroded connector pins rather than actual solenoid failure.

Common Symptoms

• Swing function becomes sluggish or completely inoperative despite other hydraulic functions working normally
• Intermittent swing speed variation or jerky rotation movements during operation
• Warning light activation on the monitor panel with reduced swing performance or complete swing lock-out
• Audible clicking from the swing motor area as the solenoid attempts to engage but fails to maintain proper control
• Machine enters derate mode, limiting swing acceleration to protect the hydraulic system from damage

Potential Causes

The E-22 code on used PC210-8 excavators typically results from age-related electrical degradation. The most common causes include:

Corroded or damaged wiring harness connectors at the swing motor solenoid valve—this PC210-8 model has a known issue with the harness routing near the center joint where constant rotation causes abrasion against the housing. Failed swing motor proportional solenoid valve itself, though less common than wiring issues in machines with over 5,000 hours. Damaged pins or moisture intrusion in the 8-pin connector between the KMC and swing motor valve. Faulty KMC output circuit, particularly in machines operated in extreme temperature environments. Low battery voltage or poor grounding affecting the entire control system's reference voltage.

How to Troubleshoot and Fix Code E-22

Step 1: Visual Inspection and Connector Assessment Begin by thoroughly inspecting the swing motor solenoid valve connector located at the swing motor assembly. Disconnect the 8-pin connector and examine for green corrosion, bent pins, or moisture. On used excavators, this connector frequently accumulates dirt and moisture. Clean contacts with electrical contact cleaner and check for proper pin tension.

Step 2: Electrical Circuit Testing Using a digital multimeter, measure resistance across the solenoid coil terminals (disconnected). The specification for the PC210-8 swing solenoid is typically 8-12 ohms at 20°C. Check for voltage supply from the KMC with ignition on—you should see approximately 12-14 volts DC at the power supply pin. Inspect wiring harness continuity from the connector back to the KMC, paying special attention to the center joint area where harness wear is common.

Step 3: Harness and Grounding Verification Trace the wiring harness through the swing bearing area where constant rotation creates friction points. Look for chafed insulation or exposed copper wire. Check machine ground connections at the swing motor mounting bolts—poor grounding causes erratic voltage readings. If wiring shows wear patterns typical of 4,000+ hour machines, consider complete harness replacement rather than spot repairs.

Step 4: Component Replacement and System Reset If electrical tests confirm solenoid failure (out-of-spec resistance or open circuit), replace the swing motor proportional solenoid valve with genuine Komatsu parts (Part #723-46-13101 or equivalent). After repairs, clear fault codes using Komatsu diagnostic software (KTEC) or a compatible scanner, then perform operational testing of swing functions at various speeds.

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu PC210-8 service manual and consider professional diagnostic assistance for complex electrical issues. Improper repairs may void warranties or create safety hazards.