What is Komatsu PC200-8 Fault Code DWA2KA?

Fault code DWA2KA on the Komatsu PC200-8 excavator indicates a malfunction in the hydraulic oil temperature sensor circuit, specifically detecting an abnormally high voltage signal or open circuit condition. This diagnostic trouble code (DTC) is generated when the machine's ECM (Engine Control Module) receives a voltage reading outside the normal operating range from the hydraulic oil temperature sensor, typically above 4.5-4.8 volts.

This code is critical for the PC200-8's performance because the hydraulic oil temperature directly affects the machine's operational efficiency and component longevity. When the ECM cannot accurately monitor oil temperature, it may trigger protective measures including reduced hydraulic flow, limited engine power, or complete system shutdown to prevent catastrophic damage to pumps, motors, and cylinders. The Komatsu PC200-8's advanced KOMTRAX monitoring system relies on precise temperature data to optimize hydraulic pressure and maintain proper viscosity ranges during operation.

Common Symptoms

When fault code DWA2KA is active, operators typically experience:

• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Hydraulic system derate with noticeably slower boom, arm, or bucket response times
• Error message display on the monitor panel showing "Hydraulic Oil Temp Sensor" or similar warning
• Intermittent loss of hydraulic power, particularly during cold starts or temperature fluctuations
• KOMTRAX system alerts sent to fleet managers if telematics are enabled

Potential Causes

The most common technical reasons for DWA2KA appearing on used PC200-8 excavators include:

• Damaged or corroded sensor connector at the hydraulic tank location, frequently caused by exposure to moisture, debris, or cleaning pressure washers
• Broken or chafed wiring harness between the sensor and ECM, particularly at flex points near the swing bearing or along the main chassis harness routing
• Failed hydraulic oil temperature sensor (NTC thermistor type) due to internal element degradation or thermal cycling stress over thousands of operating hours
• Poor ground connection at sensor mounting point caused by corrosion, paint buildup, or loose hardware
• ECM internal fault (rare) affecting the sensor input circuit or reference voltage supply
• Aftermarket sensor installation with incorrect resistance specifications for Komatsu OEM calibration

How to Troubleshoot and Fix Code DWA2KA

Step 1: Visual Inspection and Connector Check Begin by locating the hydraulic oil temperature sensor mounted on the hydraulic oil tank (typically on the left side of the PC200-8). Disconnect the sensor connector and carefully inspect both the sensor pins and harness terminals for corrosion, bent pins, moisture intrusion, or oil contamination. On used excavators, check for evidence of previous repairs, silicone sealant application, or wire splices that may indicate recurring issues. Clean connectors with electrical contact cleaner and apply dielectric grease before reconnection.

Step 2: Sensor Resistance Testing Using a digital multimeter (DMM), measure the resistance across the sensor terminals with the sensor disconnected. At 20°C (68°F) ambient temperature, the sensor should read approximately 2,000-3,000 ohms (consult your PC200-8 service manual for exact specifications). If resistance reads infinite (open circuit) or near zero ohms, the sensor has failed internally and requires replacement with a genuine Komatsu part number 7861-93-3320 or equivalent OEM sensor.

Step 3: Wiring Harness Continuity and Voltage Tests With the sensor disconnected, check for continuity between the ECM connector and the sensor harness connector using your multimeter. There should be less than 5 ohms resistance on each wire. Check for short circuits to ground by measuring resistance between each sensor wire and chassis ground (should read infinite). Next, turn the ignition to ON (engine off) and measure the reference voltage at the harness connector—you should see approximately 5 volts DC on the signal wire, indicating proper ECM output.

Step 4: Harness Routing and Wear Point Inspection On used PC200-8 machines with high hours, physically trace the sensor wiring from the tank to the main harness bundle. Pay special attention to areas where the harness passes through metal grommets, near the swing motor, or along the undercarriage where abrasion and vibration commonly cause wire insulation failure. Replace any sections showing exposed copper, cracked insulation, or previous electrical tape repairs with proper shielded automotive wire and heat-shrink connections.

Step 5: Clear Code and Verify Repair After replacing faulty components or repairing wiring, clear the fault code using Komatsu diagnostic software (KDPF) or a compatible scan tool. Operate the machine through a complete work cycle, monitoring hydraulic oil temperature on the display. The code should not return if repairs were successful. For intermittent issues common in older machines, perform multiple cold-start cycles and monitor the live data stream to confirm stable sensor readings between -40°C to +120°C range.

---

Disclaimer: This guide provides general troubleshooting information for the Komatsu PC200-8 fault code DWA2KA. Always consult your machine's official service manual and consider professional diagnostic assistance from a certified Komatsu technician, especially when working with electrical systems or if you lack proper diagnostic tools. Improper repairs may void warranties or create safety hazards.