OBD-II Code

P1400

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$40–$280

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

Check engine light

Read the full diagnostic procedureP1400 is the DPFE (Differential Pressure Feedback EGR) sensor circuit low code — the DPFE is a small black plastic box mounted on or near the EGR val…+

P1400 is the DPFE (Differential Pressure Feedback EGR) sensor circuit low code — the DPFE is a small black plastic box mounted on or near the EGR valve that measures the pressure differential across a metering orifice in the EGR tube. P1400 means the sensor signal voltage stayed below the lower limit (typically below 0.2V when it should idle at 0.9V to 1.1V key-on engine-off with no EGR flow). It is one of the most-searched Ford codes from the late 1990s through the mid-2000s.

Cheapest-first ladder

with key-on engine-off, back-probe the DPFE signal wire and check voltage — spec is 0.9V to 1.1V at rest.
A reading below 0.2V points to either a failed sensor, an open signal wire to PCM, or a missing 5V reference.
Check the 5V reference at the DPFE connector — spec is 4.9V to 5.1V; if absent, the wire is open back to the PCM. Inspect the two rubber hoses from DPFE to the steel EGR tube — they crack and fall off.
Replace the DPFE with the Motorcraft updated black-plastic-housing part DPFE15 (the original aluminum housing DPFE7 fails predictably from heat).
The expensive misdiagnosis is replacing the EGR valve ($120 to $260) when the sensor on top of it is the actual fault.

Vehicle-specific patterns1996-2004 Ford Mustang GT 4.6L 2V cars run the original aluminum DPFE that fails between 80,000 and 130,000 miles — the updated plastic Motorcraft DP…+

1996-2004Ford Mustang GT 4.6L 2V cars run the original aluminum DPFE that fails between 80,000 and 130,000 miles — the updated plastic Motorcraft DPFE15 is a direct bolt-in.
1999-2004Ford F-150 4.6L/5.4L 2V trucks suffer identical DPFE failure plus cracked steel EGR tubes from heat cycling.
2001-2007Ford Taurus 3.0L Vulcan/Duratec V6 sees P1400 with chronic regularity — the DPFE mounts on the firewall bracket and bakes from exhaust radiant heat.
1997-2002Ford Expedition 5.4L sets P1400 plus rough idle when the DPFE fails and the EGR sticks partly open from carbon.

Estimated repair$40 to $280.

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