Ford P1402 Trouble Code: Understanding, Diagnosing, and Repairing

The check engine light in your Ford is on, and your diagnostic tool displays the trouble code P1402 Ford. This code, specific to Ford group vehicles, indicates a problem with the Exhaust Gas Recirculation (EGR) system. Unlike a serious mechanical failure, P1402 is often related to a specific electronic component: the EGR Delta Pressure Sensor, also known as the DPFE sensor. Ignoring it can lead to power loss, increased fuel consumption, and failing an emissions test. This detailed guide explains the causes, symptoms, and steps to effectively resolve this issue.

What is the P1402 trouble code on a Ford?

The trouble code P1402 is defined as “Exhaust Gas Recirculation (EGR) Flow Low Detected.” Essentially, the engine control unit (ECU) constantly monitors the flow of recirculated gases through the EGR valve. To do this, it uses the DPFE (Differential Pressure Feedback EGR) sensor. This sensor measures the pressure difference between two metal tubes that run from the exhaust manifold to the EGR valve. When the ECU detects an electrical signal from the DPFE sensor that is abnormally low or inconsistent with expected values, it records the P1402 Ford code and illuminates the malfunction indicator lamp.

Symptoms associated with code P1402

A vehicle displaying this trouble code may exhibit one or more of the following symptoms:

• The “Check Engine” light is permanently on.
• Noticeable power loss, especially during acceleration.
• Irregular or unstable idle; the engine may even stall.
• Increased fuel consumption.
• In some cases, hesitation during acceleration.
• Excessive black smoke (soot) from the exhaust.

Main causes of the P1402 fault

Several factors can be the origin of this code. Here are the most common causes, listed from most to least probable:

• A faulty DPFE sensor: This is the number one cause. This sensor, often made of black plastic and located at the front of the engine, is sensitive to heat and vibrations and eventually fails.
• Clogged or leaking DPFE hoses: The two small rubber or metal tubes connecting the sensor to the EGR system can become clogged with soot or crack over time, distorting the pressure measurement.
• Wiring or connector issues: An oxidized, loose electrical connector, or cut/chafed wires between the sensor and the ECU can generate this code.
• A clogged or faulty EGR valve: Although the code directly points to the sensor, a stuck or leaking EGR valve can, in rare cases, disrupt the system enough to trigger P1402.

How to diagnose and repair code P1402?

Before replacing expensive parts, follow this logical diagnostic procedure.

Step 1: Visual Inspection

Locate the DPFE sensor (consult your Ford model’s repair manual if necessary). Carefully inspect the two small hoses connected to it. Check that they are not punctured, cracked, disconnected, or completely clogged with carbon deposits. Inspect the sensor’s electrical connector: is it properly seated and in good condition?

Step 2: Cleaning the passages

If the hoses are clogged, carefully remove them and clean them with a suitable degreaser. Take the opportunity to check and clean the orifices on the exhaust manifold where they connect, using a cloth and a small brush.

Step 3: Electrical testing of the DPFE sensor (multimeter)

This step requires a multimeter. With the ignition on (without starting the engine), measure the supply voltage at the sensor connector. You should find around 5 Volts on one pin. Then measure the return signal (usually the middle pin); the voltage should be around 0.5 to 1.5 V at idle and vary when you gently accelerate. An absence of voltage or a fixed signal indicates a faulty sensor.

Step 4: Replacing the DPFE sensor

If everything else is in order, the sensor itself is most likely defective. Replacement is straightforward: unplug the electrical connector, unscrew the two mounting bolts, remove the two hoses, and install the new sensor in reverse order. On most Fords (Focus, Fiesta, Mondeo, Kuga…), this is an accessible job with basic tools.

Conclusion

The Ford P1402 code is a common but rarely serious problem. It is essentially related to the EGR pressure measurement system. By starting with a thorough inspection of the hoses and connectors, and then proceeding to replace the DPFE sensor if necessary, you can solve this problem effectively and economically. If symptoms persist after these steps, it is advisable to consult a professional equipped with an advanced diagnostic tool to investigate the EGR system further.