What is XCMG XE490D (CM2150C-CM2150D) Fault Code 1673?

Fault Code 1673 indicates "Engine Control Module (ECM) Fuel Pump Control Circuit - Data Valid But Below Normal Operating Range." This code triggers when the ECM detects that the fuel pump control circuit voltage or signal is reading lower than the manufacturer's specified parameters, typically below 0.5 volts on Cummins CM2150 series engines.

This fault directly impacts the high-pressure fuel pump solenoid control system, which regulates fuel delivery to the common rail injectors. On the XCMG XE490D equipped with Cummins CM2150C or CM2150D engines, this circuit is critical for maintaining proper fuel pressure (typically 1,600-2,000 bar). When voltage drops below normal range, the ECM cannot accurately control fuel delivery, resulting in poor engine performance and potential engine protection mode activation.

Common Symptoms

• Check Engine Light (CEL) or amber warning lamp illuminated on the instrument cluster
• Engine derate mode engaged, limiting maximum RPM to 1,500-1,800 and reducing hydraulic power by 30-40%
• Hard starting or extended cranking time, especially during cold starts
• Rough idle with noticeable engine vibration and inconsistent RPM fluctuation (±50-100 RPM)
• Black smoke emissions under load due to incomplete combustion from improper fuel metering

Potential Causes

• Damaged wiring harness between the ECM and fuel pump solenoid, particularly at harness rub points near the engine mounting brackets (common failure area on used XCMG excavators)
• Corroded or loose connector pins at the fuel pump solenoid connector (C-141 connector on CM2150 engines)
• Failed fuel pump solenoid coil with internal short circuit or broken windings (resistance should measure 2.8-3.2 ohms)
• ECM internal driver circuit failure affecting the fuel pump control output
• Chafed or pinched wires in the engine valley area where harness passes over valve cover
• Poor ground connection at ECM chassis ground point G102

How to Troubleshoot and Fix Code 1673

Step 1: Visual Inspection Perform a thorough inspection of the fuel pump wiring harness from the ECM to the high-pressure fuel pump. On used excavators, focus on known wear points: where the harness contacts the engine block near cylinder head, routing clips that may have broken, and areas exposed to engine heat. Check for abraded insulation, melted wire jackets, or oil contamination that degrades wire integrity.

Step 2: Electrical Testing Using a digital multimeter (DMM), disconnect the fuel pump solenoid connector and measure solenoid coil resistance. Specification is 2.8-3.2 ohms at 20°C. Next, with ignition ON and engine OFF, backprobe the ECM side of the harness and measure voltage supply—should read battery voltage (12-14V). Check for voltage drop by measuring while cranking; anything above 0.5V indicates excessive resistance in the circuit.

Step 3: Connector and Ground Verification Inspect connector C-141 at the fuel pump for corrosion, bent pins, or moisture intrusion (common on machines operating in wet environments). Clean with electrical contact cleaner and apply dielectric grease. Verify ECM ground G102 has less than 0.1 ohms resistance to battery negative using a DMM in resistance mode.

Step 4: Component Replacement If wiring and connections test good, replace the fuel pump pressure control solenoid (Cummins part #4954200 or equivalent). If the problem persists after solenoid replacement, ECM internal driver circuit failure is likely, requiring ECM replacement or professional reprogramming.

For used excavators: Always inspect harness routing for modifications from previous repairs that may create new rub points, and replace any zip ties or protective loom that shows age-related deterioration.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official XCMG and Cummins service manuals for your specific engine serial number. Complex ECM diagnostics may require factory-level diagnostic software (Cummins Insite or XCMG proprietary tools) and should be performed by qualified technicians.