What is XCMG B3.9-5.9-C8.3 CM2150 Fault Code 3245-4?

Fault Code 3245-4 indicates a voltage condition below the normal operating range for the Intake Manifold Temperature (IMT) Sensor Circuit on Cummins CM2150 engines used in XCMG excavators. This diagnostic trouble code (DTC) specifically signals that the Engine Control Module (ECM) has detected an abnormally low voltage reading from the intake manifold temperature sensor circuit, typically below 0.5 volts.

The IMT sensor is critical for engine performance because it measures the temperature of air entering the combustion chamber. The ECM uses this data to calculate proper fuel injection timing, air-fuel ratios, and turbocharger boost control. When this sensor circuit fails or provides inaccurate readings, the engine management system cannot optimize combustion efficiency, potentially leading to increased emissions, reduced power output, and poor fuel economy on your XCMG machine.

Common Symptoms

Operators may experience the following issues when Code 3245-4 is active:

• Check Engine Light (CEL) illuminated on the instrument cluster with possible amber warning indicators
• Engine derate mode engaged, limiting maximum RPM and reducing available hydraulic power
• Hard starting conditions, especially in cold weather, due to incorrect fuel delivery calculations
• Rough idle or inconsistent engine performance during warm-up periods
• Black smoke from the exhaust under load, indicating improper air-fuel mixture compensation

Potential Causes

The most common technical reasons for this fault code on used XCMG excavators include:

• Open circuit or broken wire in the IMT sensor harness, particularly at flex points near the intake manifold where vibration causes conductor fatigue
• Corroded or loose connector pins at the sensor or ECM connections—extremely common on older machines exposed to moisture
• Failed intake manifold temperature sensor with internal short-to-ground or open element
• Damaged ECM sensor supply circuit, providing insufficient reference voltage (typically 5V)
• Harness chafing against engine components or frame rails, causing intermittent short-to-ground conditions
• Previous repair attempts using incorrect connector seals, allowing water intrusion into circuits

How to Troubleshoot and Fix Code 3245-4

Step 1: Visual Inspection Begin with a thorough inspection of the IMT sensor and its wiring harness. Located on the intake manifold, check for physical damage, oil contamination, or corrosion on the connector. On used excavators, pay special attention to harness routing near hot exhaust components or areas where cables may rub against metal surfaces during engine movement.

Step 2: Electrical Testing Using a digital multimeter (DMM), disconnect the IMT sensor connector and measure resistance across the sensor terminals. A functional sensor typically reads 2,000-3,000 ohms at room temperature. Next, check for 5-volt reference supply from the ECM with the key on, engine off. Measure continuity on the signal wire and ground circuit back to the ECM—readings above 5 ohms indicate excessive resistance from corrosion or damaged wiring.

Step 3: Sensor Replacement and Verification If electrical tests confirm sensor failure, replace the IMT sensor using OEM or quality aftermarket parts. Before installation on used machines, clean the sensor mounting bore and apply anti-seize compound to threads. After replacement, clear fault codes using Cummins INSITE diagnostic software or compatible scan tool, then perform a road test to verify repair. Monitor live data to confirm the sensor reads appropriate temperature values (typically 80-120°F ambient).

Critical for Used Equipment: Always inspect connector seals and apply dielectric grease to prevent future corrosion—a leading failure mode on aging excavators.

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Disclaimer: This guide provides general troubleshooting information. Always consult qualified diesel technicians and refer to manufacturer service manuals for your specific XCMG model before performing repairs. Improper diagnostics may cause additional engine damage or safety hazards.