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
This is a powertrain code, so a basic OBD-II reader can read it. These read P0406.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the 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 tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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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.