AutoCodesMazda – P1401 Mazda

P1401 Mazda Code - DPFE Sensor Circuit High

Quick Answer

The purpose of the Exhaust Gas Recirculation (EGR) system on your engine is to limit oxides of nitrogen (NOx) emissions. Common causes include Faulty Differential Pressure Feedback Electronic (DPFE) sensor, Differential Pressure Feedback Electronic (DPFE) sensor harness is open or shorted, Differential Pressure Feedback Electronic (DPFE) sensor circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P1401 Mazda indicates DPFE Sensor Circuit High.
Common causes
Common causes include Faulty Differential Pressure Feedback Electronic (DPFE) sensor, Differential Pressure Feedback Electronic (DPFE) sensor harness is open or shorted, Differential Pressure Feedback Electronic (DPFE) sensor circuit poor electrical connection.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
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Code Popularity 25,928
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Aug 18, 2019
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Code P1401 Mazda Description

The purpose of the Exhaust Gas Recirculation (EGR) system on your engine is to limit oxides of nitrogen (NOx) emissions. This is done by redirecting small amounts of exhaust gas back through the upper intake to get mixed in with the air/fuel charge. The resultant diluted air/fuel mixture (i.e., less oxygen per cubic foot) burns cooler and combustion chamber temperatures are reduced accordingly, thereby lowering NOx emissions.
The DPFE/EGR system is controlled by the Powertrain Control Module (PCM). The system employs an EGR Valve, an Electronic Vacuum Regulator (EVR), and a Delta Pressure Feedback EGR sensor (DPFE).
The DPFE Sensor measures EGR flow across an orifice located inside the special EGR Tube. The orifice is positioned between two hose ports coming off the tube which are connected to the DPFE sensor with special heat-resistant hoses. When the EGR Valve is open, a pressure differential is created across the orifice (intake manifold pressure vs. exhaust pressure). By design, this difference in pressure is measured by the DPFE sensor in terms of voltage. The DPFE voltage signal output to the PCM is directly proportional to the flow of exhaust gas entering the intake manifold.
OBDII Code P1401 Mazda - DPFE Sensor Circuit High - AutoCodes.com
P1401 Mazda Code - DPFE Sensor Circuit High

What are the Possible Causes of the DTC P1401 Mazda?

  • Faulty Differential Pressure Feedback Electronic (DPFE) sensor
  • Differential Pressure Feedback Electronic (DPFE) sensor harness is open or shorted
  • Differential Pressure Feedback Electronic (DPFE) sensor circuit poor electrical connection

How to Fix the DTC P1401 Mazda?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1401 Mazda code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1401 Mazda code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1401 Mazda Code

1. What does the OBDII code P1401 mean on a Mazda?

P1401 indicates a "DPFE Sensor Circuit High," meaning the Differential Pressure Feedback EGR (DPFE) sensor is detecting a higher-than-expected voltage, typically related to the EGR system.

2. What are the common symptoms of P1401 in a Mazda?

Symptoms may include the check engine light turning on, poor engine performance, rough idling, decreased fuel efficiency, and potential engine hesitation or stalling.

3. What causes the P1401 code to appear on a Mazda?

Common causes include a faulty DPFE sensor, clogged or damaged EGR passages, wiring or connector issues in the sensor circuit, or a malfunctioning EGR valve.

4. Can a dirty EGR valve cause the P1401 code?

Yes, a dirty or clogged EGR valve can restrict exhaust gas flow, leading to incorrect readings by the DPFE sensor and triggering the P1401 code.

5. How do I fix the P1401 code on my Mazda?

Possible fixes include replacing the DPFE sensor, cleaning or replacing the EGR valve, inspecting and repairing wiring or connectors, and clearing any blockages in EGR passages.

6. Can I drive my Mazda with the P1401 code?

While driving with P1401 may be possible, it can lead to poor performance and increased emissions. Prolonged driving without repair can cause further engine damage.

7. How can I test the DPFE sensor to diagnose the P1401 code?

You can use a multimeter to check the sensor's voltage output against manufacturer specifications or use a scan tool to monitor EGR system performance in real-time.

8. Is replacing the DPFE sensor always necessary for P1401?

No, replacing the DPFE sensor isn’t always necessary. First, verify the sensor's condition and check for issues like clogged EGR passages or wiring problems.

9. What tools are needed to troubleshoot the P1401 code in a Mazda?

Common tools include a multimeter, scan tool, vacuum gauge, and basic hand tools for removing and inspecting EGR system components.

10. How much does it cost to fix the P1401 code in a Mazda?

The repair cost can vary. Replacing a DPFE sensor typically costs $100–$300, while cleaning or repairing the EGR system may add labor costs depending on the severity of the issue.

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