P0406 on Ford
Exhaust Gas Recirculation Sensor "A" Circuit High
P0406 on Ford vehicles indicates exhaust gas recirculation sensor "a" circuit high. Au7o has documented this code across 1 Ford model — most commonly on F-150. 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. Typical repair costs on Ford range from $50 to $250, depending on the specific model and root cause.
Common Causes of P0406
- •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)
P0406 on Ford by Model
Ford F-150(1 issue)
- DPFE / EGR Pressure Sensor Failure — Rough Idle, Stalling, and P0401 (2-Valve Triton)1997-2004
The Delta Pressure Feedback EGR (DPFE) sensor and the EGR throttle-body spacer passages are a chronic Check-Engine source on 1997-2004 4.2L/4.6L/5.4L trucks. The ceramic DPFE sensor drifts or cracks, and the narrow 90-degree EGR elbow passages carbon up until flow is blocked, setting P0401 (insufficient EGR flow). The result is a rough idle, stumble or stall when coming to a stop, hesitation, and reduced fuel economy. It is frequently misdiagnosed as the EGR valve itself.
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View P0406 across all makes →Frequently Asked Questions
What does P0406 mean on Ford?▼
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. On Ford specifically, this code is documented across 1 model.
What causes P0406 on Ford vehicles?▼
Common causes on Ford: 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). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0406 on a Ford?▼
Repair costs on Ford range from $50 to $250, depending on the specific model and root cause.
Which Ford models have P0406 documented?▼
Au7o has documented P0406 on 1 Ford model: F-150.