What is Caterpillar C4.4 Fault Code 2246-6?

Fault Code 2246-6 indicates "Injector Cylinder 6 - Current Below Normal or Open Circuit." This diagnostic trouble code (DTC) signals that the Engine Control Module (ECM) has detected abnormally low electrical current flowing to the fuel injector on cylinder 6, or the circuit is completely open (disconnected).

The Caterpillar C4.4 engine relies on precision electronic fuel injection for optimal performance and emissions compliance. When the ECM cannot properly energize injector 6, that cylinder may misfire or fail to fire entirely, leading to power loss, rough operation, and increased fuel consumption. In used excavators, this code often points to wiring degradation or connector corrosion rather than injector failure itself.

Common Symptoms

When fault code 2246-6 is active, operators typically experience:

• Check Engine Light or Malfunction Indicator Lamp (MIL) illuminated on the instrument cluster
• Noticeable rough idle or engine shaking, especially when cold
• Loss of power during digging or lifting operations due to one cylinder not contributing
• Black or white smoke from the exhaust under load
• Possible engine derate mode limiting RPM to protect the engine from damage

Potential Causes

The most common technical causes for this fault code on used C4.4 engines include:

• Damaged or corroded wiring harness between the ECM and cylinder 6 injector, particularly at harness rub points near the valve cover or engine mounts
• Faulty electrical connector at the injector itself—corrosion or moisture intrusion is common on older machines
• Failed fuel injector solenoid on cylinder 6 due to internal coil breakage or wear
• ECM internal driver circuit failure (less common but possible on high-hour machines)
• Broken or frayed wires within the injector harness bundle, often caused by vibration over thousands of operating hours

How to Troubleshoot and Fix Code 2246-6

Step 1: Visual Inspection Begin by inspecting the injector harness and connector on cylinder 6. Look for obvious damage, frayed wires, oil contamination, or corrosion on connector pins. On used excavators, check known rub points where the harness contacts the valve cover or chassis components.

Step 2: Electrical Testing Using a digital multimeter (DMM), disconnect the injector connector and measure resistance across the injector solenoid terminals. A typical C4.4 injector should read approximately 0.3 to 1.5 ohms. An open circuit (infinite resistance) confirms injector coil failure. Also check for continuity between the harness connector and ECM pins to rule out open wiring.

Step 3: Advanced Diagnostics Connect Caterpillar Electronic Technician (Cat ET) diagnostic software to monitor real-time injector current. The ECM should command approximately 18-22 amps to each injector. If voltage is present but current remains low, suspect a failing injector. If no voltage appears, investigate ECM output drivers or harness shorts to ground.

Step 4: Component Replacement Replace faulty components in this order: connector/harness first (most common on used machines), then injector, and finally ECM if all else checks good. Always apply dielectric grease to connectors during reassembly to prevent future corrosion.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Caterpillar service manual for your specific machine serial number and seek professional diesel technician assistance for complex electrical diagnostics or injector replacement.