What is Kobelco SK200-8 Fault Code B164?

Fault Code B164 on the Kobelco SK200-8 excavator indicates a malfunction in the Air Conditioner Pressure Sensor Circuit. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal voltage signal from the A/C pressure sensor, which monitors refrigerant pressure in the climate control system.

The A/C pressure sensor plays a critical role in protecting the air conditioning compressor from damage due to excessively high or low refrigerant pressure. When the ECM cannot receive accurate pressure readings, it may disable the A/C system entirely to prevent compressor failure. For operators working long hours in extreme temperatures, this fault directly impacts cab comfort and can reduce productivity. On used Kobelco SK200-8 machines, this code often appears due to age-related sensor degradation or electrical connection issues rather than actual A/C system failures.

Common Symptoms

When Code B164 is active on your SK200-8, you may experience:

• A/C system completely inoperative – compressor will not engage regardless of control settings
• Warning indicator illuminated on the instrument cluster or monitor panel
• Intermittent A/C operation – system works briefly then shuts down unexpectedly
• No cold air from vents even when A/C button is activated
• ECM storing fault code visible through diagnostic software or display

Potential Causes

The most common technical reasons for Code B164 on used SK200-8 excavators include:

• Failed A/C pressure sensor – internal sensor element degradation (common after 5,000+ operating hours)
• Corroded or loose connector at the pressure sensor harness (located near the A/C compressor)
• Damaged wiring harness – abrasion from vibration or contact with moving components in the engine compartment
• Open or short circuit in the sensor signal wire between the sensor and ECM
• Low refrigerant charge causing abnormally low pressure readings that trigger the fault
• ECM software glitch or faulty ECM module (less common)

How to Troubleshoot and Fix Code B164

Step 1: Visual Inspection Locate the A/C pressure sensor mounted on the high-pressure line near the compressor. Inspect the sensor connector for corrosion, moisture, or damaged pins. On used excavators, check for wiring harness chafing against the engine block or frame – a common failure point due to engine vibration over time.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to check sensor resistance (typically 100-300 ohms at room temperature; consult Kobelco service manual for exact specifications). Test voltage supply from the ECM at the harness connector – should read approximately 5 volts with ignition on. Check for continuity between the sensor ground pin and chassis ground.

Step 3: Refrigerant Pressure Check Connect A/C manifold gauges to verify actual system pressures. Low refrigerant (below 30 PSI on low side) can trigger false sensor faults. If pressures are normal but sensor readings are abnormal via diagnostic software, replace the pressure sensor.

Step 4: Advanced Diagnostics Use Kobelco diagnostic software (KDWS or compatible scan tool) to monitor live sensor data. Compare actual gauge readings with ECM-reported values. If voltage remains at 0V or 5V regardless of pressure changes, suspect wiring issues or ECM fault. For used machines, always apply dielectric grease to connectors after repairs to prevent future corrosion.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Kobelco service manual for your specific machine serial number and consider professional diagnosis for complex electrical issues. Refrigerant handling requires EPA-certified technicians.