What is Sany Excavator Fault Code P168?

Fault Code P168 indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading outside the acceptable operating range. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects voltage signals from the coolant temperature sensor that are either too high, too low, or inconsistent with expected engine operating conditions.

The coolant temperature sensor plays a critical role in Sany excavators by providing real-time data to the ECM about engine thermal status. This information directly affects fuel injection timing, idle speed control, and engine protection protocols. When P168 activates, the ECM may default to a pre-programmed temperature value, compromising fuel efficiency and potentially allowing engine overheating conditions to develop undetected.

Common Symptoms

Operators may experience the following when Code P168 is active:

• Check Engine Light or malfunction indicator lamp illuminated on the instrument cluster
• Hard starting or extended cranking times, especially during cold weather conditions
• Rough idle or irregular engine RPM fluctuations during warm-up periods
• Engine derate mode activation, limiting power output to protect components
• Cooling fans running continuously at high speed regardless of actual engine temperature
• Excessive black smoke from exhaust due to improper fuel mixture compensation

Potential Causes

Several factors commonly trigger P168 in used Sany excavators:

• Failed coolant temperature sensor with internal resistance drift or complete open/short circuit failure
• Damaged or corroded wiring harness connections at the sensor connector, particularly where harnesses route near hot exhaust components
• Corrosion or moisture intrusion in the sensor connector pins—extremely common in machines with high hour counts or outdoor storage
• Low coolant level causing air pockets around the sensor, producing erratic readings
• Defective ECM with internal processing errors (rare but possible in older units)
• Aftermarket or incorrect replacement sensors with incompatible resistance curves

How to Troubleshoot and Fix Code P168

Step 1: Visual Inspection Begin by checking coolant level in the radiator and expansion tank. Inspect the coolant temperature sensor (typically located on the engine block or thermostat housing) and its connector for obvious damage, corrosion, or coolant leaks. On used excavators, carefully examine the wiring harness for chafing points where it contacts the engine block or frame rails.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure sensor resistance. At room temperature (20°C/68°F), resistance should typically range between 2,000-3,000 ohms (consult Sany service manual for exact specifications). Test harness continuity from the sensor connector back to the ECM, checking for opens or shorts to ground.

Step 3: Sensor Replacement and Verification If sensor resistance is out of specification or harness damage is found, replace the faulty component using OEM or high-quality aftermarket parts. Apply dielectric grease to connector pins before reassembly to prevent future corrosion. Clear the fault code using Sany diagnostic software or a compatible scan tool, then monitor during a complete heat cycle.

For used excavators with persistent P168 codes after sensor replacement, investigate potential ECM issues or coolant system air pockets requiring professional bleeding procedures.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sany service manual for your specific model and consider professional diagnostic assistance for complex electrical issues.