P0406 on 1997-2004 Ford F-150 (XL, XLT, Lariat, FX4, King Ranch) — Exhaust Gas Recirculation Sensor "A" Circuit High
1 vehicles · 1 makes · $50-$250 repair
Most Reported On
P0406 is an OBD-II diagnostic trouble code meaning “Exhaust Gas Recirculation Sensor "A" Circuit High.” The PCM reads a higher-than-expected voltage from EGR position/feedback sensor A, indicating a short to voltage, open signal, or failed sensor on an electronic EGR valve. This code is most commonly reported on 1997-2004 Ford F-150 (XL, XLT, Lariat, FX4, King Ranch), with repair costs ranging from $50 to $250.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0406, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does P0406 mean?
P0406 stands for "Exhaust Gas Recirculation Sensor "A" Circuit High." The PCM reads a higher-than-expected voltage from EGR position/feedback sensor A, indicating a short to voltage, open signal, or failed sensor on an electronic EGR valve.
What are the most common causes of P0406?
The most common causes of P0406 are: Failed EGR position sensor A, Short to voltage in signal wire, Open ground circuit raising signal voltage, Corroded or damaged EGR connector, Faulty PCM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0406?
Repair costs for P0406 range from $50 to $250, depending on the vehicle and root cause.
Which vehicles are affected by P0406?
Au7o has documented P0406 across 1 vehicle models from 1 manufacturers: Ford.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.