What is Doosan Excavator Fault Code P2267?

Fault Code P2267 indicates a Secondary Air Injection System Control "A" Circuit Low condition detected by the Engine Control Module (ECM). This diagnostic trouble code specifically relates to the secondary air injection system's electrical circuit, which supplies additional oxygen to the exhaust stream during cold starts to reduce emissions and accelerate catalytic converter warm-up.

In Doosan excavators, this code triggers when the ECM detects abnormally low voltage or an open circuit in the secondary air injection pump control circuit. The secondary air system is critical for meeting emissions standards and ensuring optimal engine performance during warm-up cycles. When this system fails, your machine may struggle with increased emissions, extended warm-up periods, and potential non-compliance with environmental regulations—particularly important for used equipment operating under strict emission requirements.

Common Symptoms

• Check Engine Light (CEL) illuminated on the instrument cluster with reduced engine performance during cold starts
• Extended cranking time or rough idle conditions when starting the excavator in cold ambient temperatures
• Noticeable increase in black or gray exhaust smoke during the initial 2-5 minutes of operation
• Engine derate mode activation in severe cases, limiting maximum RPM and hydraulic system performance
• Audible absence of the secondary air pump operation during startup (normally produces a distinct humming sound for 60-120 seconds)

Potential Causes

• Secondary air injection pump relay failure or corroded relay contacts causing insufficient power delivery to the pump motor
• Damaged or chafed wiring harness between the ECM and secondary air pump, commonly occurring where harnesses route near sharp metal edges or moving components
• Failed secondary air injection pump motor due to carbon brush wear or seized bearings (especially common in machines with 5,000+ operating hours)
• Corroded or loose electrical connectors at the pump assembly—typical in equipment exposed to wet or dusty environments
• Blown fuse in the secondary air injection system circuit within the main fuse panel
• ECM internal driver circuit failure (rare, but possible in older machines with electrical system history)

How to Troubleshoot and Fix Code P2267

Step 1: Visual Inspection and Connector Verification Begin by locating the secondary air injection pump (typically mounted on the engine's right side near the exhaust manifold). Inspect all electrical connectors for corrosion, moisture intrusion, or loose pins. On used excavators, pay special attention to connector seals that may have degraded over time. Clean connectors with electrical contact cleaner and apply dielectric grease before reconnection.

Step 2: Electrical Circuit Testing Using a digital multimeter, check for battery voltage (typically 24V on Doosan machines) at the pump connector with the ignition on and engine cold. If no voltage is present, trace back to the relay and fuse. Test the relay by swapping it with an identical relay from another system temporarily. Check wiring continuity between the ECM (Pin reference available in service manual) and the pump connector—resistance should be less than 5 ohms.

Step 3: Secondary Air Pump Functional Test If voltage and ground circuits test properly, apply direct power to the pump motor terminals to verify pump operation. A functioning pump should activate immediately with audible airflow. For used machinery, remove the pump and inspect for carbon buildup or bearing seizure—common failure points after extended service. Check the air delivery hoses for cracks or disconnections that could affect system pressure readings.

Step 4: Advanced Diagnostics Connect Doosan-specific diagnostic software (DX-DIAG or equivalent dealer software) to monitor real-time secondary air system parameters and command pump activation. Monitor ECM current draw during pump operation (typical draw: 8-15 amps). If the system passes all tests but the code persists, suspect ECM driver circuit failure requiring module replacement or repair.

Disclaimer: This guide provides general troubleshooting information for educational purposes. Always consult your Doosan service manual for model-specific procedures, torque specifications, and safety precautions. For complex electrical diagnostics or ECM programming, professional consultation with a certified Doosan technician is strongly recommended, especially when dealing with emission-critical systems on used equipment.