P1400
FordDPFE Circuit Low Input
The engine computer has detected a low electrical input from the DPFE sensor circuit. The DPFE sensor measures pressure changes associated with EGR flow, helping the computer assess whether exhaust gas is being recirculated as intended. A low signal can come from an electrical fault or a problem affecting the sensor's pressure reading; this code does not prove the sensor itself is bad.
⚠️ Before You Begin (Safety First)
This code is not usually an immediate stop-driving condition by itself. Drive cautiously and arrange diagnosis; stop if the engine stalls, runs severely rough, or loses power in a way that makes driving unsafe.
Common Symptoms
- There may be no noticeable symptoms if the fault is intermittent or the engine continues to run normally.
- The check-engine light may be on because the computer has detected a low DPFE circuit input.
- Incorrect EGR-flow feedback may contribute to rough running, hesitation or reduced performance, depending on how the fault affects EGR operation.
- Fuel economy or emissions performance may be affected if EGR flow is not being monitored or controlled correctly.
Common Causes
- A faulty DPFE sensor may produce an input that is too low.
- Damaged, loose or corroded wiring or connector contacts can interfere with the sensor circuit.
- A circuit fault, such as a signal short to ground or a problem with the circuit's power or ground, can cause a low input.
- Leaking, blocked, disconnected or damaged DPFE pressure hoses can interfere with the pressure reading.
- An EGR valve or passage problem may affect the pressure difference the sensor is meant to measure, though it does not by itself prove an electrical circuit failure.
Diagnostic Steps
- Record the code and any related codes before clearing anything; freeze-frame information can help show the conditions when the fault was detected.
- With the engine off and cool, visually inspect the DPFE sensor connector and accessible wiring for looseness, corrosion, rubbing or damage.
- Check accessible DPFE pressure hoses for disconnection, cracks, kinks or blockage; do not work near hot exhaust parts.
- If the code returns, avoid replacing the sensor based on the code alone. Have the circuit and sensor response tested using model-, year- and engine-specific service information.
When to Call a Professional
Confirm the code and review related codes and freeze-frame data. Inspect the DPFE sensor wiring, connector and pressure hoses, then test circuit power, ground and signal using the correct vehicle wiring information. Check whether the signal responds appropriately during controlled EGR operation. Verify the cause before replacing parts.
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Commonly Asked Questions
Does P1400 mean the DPFE sensor must be replaced?
No. It identifies a low input in the DPFE circuit, not a confirmed failed sensor. Wiring, connector, pressure-hose or EGR-system issues can also affect diagnosis.
What does the DPFE sensor do?
It measures a pressure difference associated with EGR flow. The engine computer uses that information to assess EGR operation.
Can I keep driving with P1400?
If the vehicle runs normally, cautious driving to arrange diagnosis is generally reasonable. Stop if it stalls, runs severely rough or becomes unsafe to control.
Could a hose problem cause this code?
A damaged, disconnected or blocked pressure hose can distort the sensor's pressure reading. The electrical circuit should still be checked because the code specifically identifies a low circuit input.
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