Fix P1406: EGR Pressure Feedback Sensor Circuit High Input – Trust iCarsoft CR Eagle
If your check engine light lights up and you notice reduced fuel efficiency, rough idling, or failed emissions tests, your diagnostic tool may retrieve P1406. This trouble code points to a critical issue with your vehicle’s Exhaust Gas Recirculation (EGR) System—specifically an “EGR Pressure Feedback Sensor Circuit High Input” malfunction. The EGR pressure feedback sensor (also called a differential pressure sensor) monitors EGR flow and sends data to the Engine Control Unit (ECU), and a high input signal means the sensor is transmitting abnormal voltage. Ignoring P1406 can lead to increased emissions, engine wear, and costly repairs. In this guide, we’ll break down P1406, its causes, and how the iCarsoft CR Eagle—an OE-level diagnostic tool—helps you resolve it efficiently.
What Exactly Is Fault Code P1406?
P1406 is a manufacturer-specific OBD-II trouble code most commonly defined as “EGR Pressure Feedback Sensor Circuit High Input”. Key details to understand:
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The EGR pressure feedback sensor measures the pressure difference in the EGR system to verify if exhaust gas is flowing correctly through the EGR valve.
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A “high input” means the ECU detects a voltage signal from the sensor that exceeds the normal operating range (typically 0.5V to 4.5V, depending on the vehicle).
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This indicates a disruption in the sensor’s circuit—either the sensor itself is faulty, wiring is damaged, or there’s a blockage in the EGR system affecting pressure readings.
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P1406 applies to 1996+ OBD-II compliant gasoline and diesel vehicles with EGR systems, including popular makes like Ford, Toyota, Honda, BMW, Mercedes-Benz, and VW.
Why Does P1406 Happen? Common Causes
To fix P1406, identify the root cause first. Here are the most frequent triggers:
Faulty EGR Pressure Feedback Sensor
Internal electrical failure or contamination causes the sensor to send consistently high voltage signals.
Wiring or Connector Issues
Frayed, shorted, or corroded wires, or loose connectors between the sensor and ECU, create a high-resistance circuit.
Clogged EGR Passages or Valve
Carbon buildup in EGR tubes, ports, or the valve blocks gas flow, leading to abnormal pressure readings.
Leaking EGR Hoses
Cracked or loose EGR hoses allow air leaks, disrupting pressure sensing and triggering high input signals.
Faulty EGR Valve
A stuck-open or malfunctioning EGR valve alters pressure dynamics in the system.
ECU Malfunction & Sensor Port Contamination
Rarely, a faulty ECU misinterprets signals; soot/debris clog sensor ports, preventing accurate pressure readings.
Symptoms of P1406
P1406 often presents noticeable symptoms, including:
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Illuminated check engine light (primary indicator).
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Reduced fuel efficiency due to incorrect EGR flow regulation.
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Rough idling or engine misfires (especially at low speeds).
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Failed emissions tests (high NOx emissions).
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Sluggish acceleration or loss of power.
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Increased exhaust odor from unregulated exhaust gas flow.
Why the iCarsoft CR Eagle Is Perfect for P1406
Basic scanners only read P1406, but the iCarsoft CR Eagle offers advanced features that simplify diagnosing and fixing the issue. Here’s why it stands out:
Full EGR System Scans
Dives deep into the EGR pressure sensor, wiring, valve, and passages to pinpoint whether the issue is the sensor, connectivity, or blockage.
Live Data Monitoring
Views real-time sensor voltage, EGR pressure, and ECU feedback to confirm if the signal is abnormally high.
Powerful Bi-directional Control
Sends commands to test the EGR valve and sensor—verifies if components respond correctly without disassembly.
Global Vehicle Coverage
Works with 58 major vehicle makes, including gasoline/diesel models and OBDI vehicles (with included adaptors like Benz38Pin and BMW20Pin).
Advanced Hardware
Features a 10.1-inch touchscreen, 4GB RAM + 128GB ROM, and dual-band Wi-Fi/Bluetooth for smooth wireless diagnostics.
ECU Coding & Adaptation
Reconfigures the ECU after sensor or EGR valve replacement to ensure seamless compatibility.
Bonus Features
Built-in TPMS programming (with 4 sensors) and a videoscope to inspect EGR passages for clogs.
Lifetime Free Updates & Support
Stays compatible with new vehicle models and provides expert technical support.
How to Diagnose & Fix P1406 with the iCarsoft CR Eagle (Step-by-Step)
Step 1: Connect the Tool
Plug the CR Eagle’s OBD-II cable into your vehicle’s port (under the dashboard). Use included OBDI adaptors for older models.
Step 2: AutoVIN Identification
The tool automatically retrieves your vehicle’s make, model, and VIN—no manual entry needed.
Step 3: Scan for Codes
Select “Full System Scan” or “Engine System Scan” to pull up P1406 and related codes (e.g., P0401 for EGR flow insufficient).
Step 4: Check Live Data
Navigate to “Live Data” to monitor EGR pressure feedback sensor voltage. A reading above the vehicle’s normal range confirms a high input issue.
Step 5: Run Bi-directional Tests
Use the “Active Test” function to activate the EGR valve. Monitor sensor voltage changes—no response indicates a faulty sensor or wiring; abnormal changes point to EGR system blockages.
Step 6: Inspect Components
Use the CR Eagle’s videoscope to check EGR passages for carbon buildup. Inspect the sensor for contamination and wiring for damage.
Step 7: Repair or Replace Parts
Clean EGR passages/valve (if clogged), replace the faulty sensor, repair wiring/connectors, or fix leaking hoses.
Step 8: Clear the Code & Verify
Use the CR Eagle to erase P1406, take a test drive, and re-scan to ensure the code doesn’t return. Use ECU adaptation to calibrate the new sensor.
FAQs: Your P1406 Questions Answered
Can I drive with P1406?
You can drive short distances, but increased emissions and engine strain make prompt diagnosis with the CR Eagle critical. Avoid long trips or high speeds.
Will the CR Eagle work with my car?
Yes! It supports 58 major vehicle makes and all 1996+ OBD-II compliant vehicles with EGR systems. It also works with OBDI models using included adaptors.
Do I need mechanical experience to use the CR Eagle?
No! Its 10.1-inch touchscreen, AutoVIN function, and clear prompts make it user-friendly for DIYers. Lifetime technical support is available if you need help.
Can the CR Eagle distinguish between a faulty sensor and wiring issues?
Absolutely. Live data shows if voltage is consistently high (faulty sensor) or erratic (wiring issues). Bi-directional tests confirm if the sensor responds to EGR valve activation.
Do I need to replace the sensor, or can I clean it?
The CR Eagle’s live data and videoscope help you decide—cleaning works for contaminated sensor ports; replacement is needed for electrical sensor failure.
Is the CR Eagle better than a basic scanner for P1406?
Yes. Basic scanners only read codes, but the CR Eagle offers live data, bi-directional tests, and videoscope integration—helping you avoid unnecessary sensor replacements.
How often should I update the CR Eagle?
Update every 3–6 months via free Wi-Fi updates to ensure compatibility with new EGR system designs and diagnostic algorithms.
Does the CR Eagle come with everything I need?
Yes! It includes an OBD-II cable, 4 OBDI adaptors, 4 TPMS sensors, a videoscope, and a carrying case—no extra tools required for P1406 diagnosis.
Final Thoughts: Don’t Let P1406 Disrupt Your EGR System
P1406 is a warning that your EGR pressure feedback sensor is malfunctioning, putting your vehicle’s emissions compliance and engine health at risk. The iCarsoft CR Eagle isn’t just a tool for fixing P1406—it’s a comprehensive diagnostic solution that handles over 40 high-level service functions, making it a long-term investment for all your vehicle maintenance needs. Whether you’re a DIY enthusiast or a professional, the CR Eagle gives you the power to diagnose and fix P1406 right from your garage.
Invest in the iCarsoft CR Eagle today to tackle P1406 and hundreds of other codes—keep your vehicle running cleanly and efficiently.
