What is XCMG XE490D (CM2150 C/D) Fault Code 1698?

Fault Code 1698 indicates a high voltage condition in the Engine Position Sensor Circuit (Camshaft Position Sensor), specifically detecting an open circuit or voltage reading above the manufacturer's threshold. This code is triggered when the Electronic Control Module (ECM) detects a voltage signal exceeding 4.5 volts on the camshaft position sensor circuit, which normally operates between 0.5-4.5 volts on Cummins CM2150 series engines powering the XCMG XE490D excavator.

The camshaft position sensor is critical for precise fuel injection timing and engine synchronization. When this sensor circuit fails, the ECM cannot accurately determine piston position, directly impacting combustion efficiency, fuel economy, and overall engine performance. For used excavators operating in demanding construction environments, this fault can lead to immediate derate conditions that severely limit productivity.

Common Symptoms

• Check Engine Light (CEL) illuminated on the instrument cluster with possible engine derate to 1500 RPM
• Hard starting conditions or extended cranking time, especially when the engine is cold
• Rough idle with noticeable engine vibration and inconsistent RPM fluctuation
• Loss of power during high-demand operations like digging or lifting heavy loads
• Increased fuel consumption and visible black or gray exhaust smoke under load

Potential Causes

The most common technical failures triggering Code 1698 on used XCMG excavators include:

• Damaged wiring harness between the camshaft position sensor and ECM, particularly at known rub points near the engine block mounting brackets
• Corroded or moisture-infiltrated connectors at the sensor itself, common in machines operating in wet or muddy conditions
• Failed camshaft position sensor due to internal circuit breakdown or heat degradation (typical after 5,000+ operating hours)
• Broken or frayed sensor signal wire caused by engine vibration over time
• ECM internal fault (rare, but possible in high-hour machines with electrical system stress)
• Intermittent short-to-power condition where the sensor wire contacts a voltage source

How to Troubleshoot and Fix Code 1698

Step 1: Visual Inspection Begin with a thorough inspection of the camshaft position sensor located on the engine's timing case cover. Check the electrical connector for corrosion, bent pins, or moisture intrusion. On used excavators, pay special attention to harness routing near engine mounts and moving components where vibration causes insulation wear.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across the sensor terminals (should read 200-1,000 ohms for most CM2150 sensors). Next, check for voltage at the harness connector with the key on, engine off—you should see approximately 5 volts on the reference wire. Any reading above 4.8 volts indicates a wiring issue.

Step 3: Circuit Continuity Check Test for continuity and shorts in the wiring between the sensor and ECM connector. Check specifically for short-to-power conditions by measuring voltage on the signal wire with the sensor disconnected—any voltage present indicates damaged insulation contacting a power source.

Step 4: Sensor Replacement and Verification If wiring checks pass, replace the camshaft position sensor with an OEM or quality aftermarket part. After installation, clear codes using INSITE diagnostic software (Cummins-specific) or compatible scan tool, then perform a test run under load. For used machines, apply dielectric grease to connectors to prevent future corrosion.

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Disclaimer: This guide provides general diagnostic information. Always consult the official XCMG service manual and consider professional evaluation by a certified Cummins technician, especially for complex electrical diagnostics or ECM programming issues.