Faulty EGR temperature sensor itself, often due to internal failure or corrosion.; Damaged or corroded wiring harness and connector at the sensor.; Open or short circuit in the sensor signal or ground circuit.; Carbon buildup or blockage in the EGR passage affecting sensor readings.; Failed EGR valve or solenoid causing incorrect flow and temperature signals.; ECM software issue or internal fault, though this is less common.

DTC codes / Nissan codes / P1401

P1401 · NissanEGR Temperature Sensor

Q: What does code P1401 mean?

EGR Temperature Sensor. P1401 on Nissan vehicles indicates that the engine control module (ECM) has detected an abnormal signal from the exhaust gas recirculation (EGR) temperature sensor circuit. The ECM monitors this sensor to verify EGR flow and temperature, and it sets the code when the sensor voltage or resistance falls outside the expected range for the current operating conditions.

P1401 on Nissan vehicles indicates that the engine control module (ECM) has detected an abnormal signal from the exhaust gas recirculation (EGR) temperature sensor circuit. The ECM monitors this sensor to verify EGR flow and temperature, and it sets the code when the sensor voltage or resistance falls outside the expected range for the current operating conditions.

SystemPowertrain

Code typeNissan specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Slight rough idle or hesitation during acceleration if the EGR system remains open or closed incorrectly.
Reduced fuel economy in some cases due to improper EGR flow affecting combustion efficiency.
Intermittent engine stumble or surge at steady cruising speeds.
Failed emissions test due to increased oxides of nitrogen (NOx) levels.
In rare cases, a no-start condition if the sensor shorts and affects the ECM's reference voltage.

Common causes, most likely first

Faulty EGR temperature sensor itself, often due to internal failure or corrosion.
Damaged or corroded wiring harness and connector at the sensor.
Open or short circuit in the sensor signal or ground circuit.
Carbon buildup or blockage in the EGR passage affecting sensor readings.
Failed EGR valve or solenoid causing incorrect flow and temperature signals.
ECM software issue or internal fault, though this is less common.

How to diagnose and fix it

Connect a scan tool and verify P1401 is current; check freeze frame data for sensor voltage and engine conditions.
Inspect the EGR temperature sensor connector and wiring for corrosion, loose pins, or damage; repair as needed.
Measure the sensor's resistance or voltage with a multimeter and compare to Nissan specifications for the given temperature.
Check the EGR passage and valve for carbon blockage; clean or replace components if restricted.
Test the sensor signal circuit for continuity and shorts to ground or power; repair wiring faults.
Replace the EGR temperature sensor if it fails electrical testing, then clear codes and verify the repair with a test drive.
If the code persists after sensor replacement, diagnose the EGR valve and ECM circuits before condemning the ECM.

EGR temperature sensor diagnostics that save time

A common misdiagnosis is replacing the EGR valve when the actual fault is a corroded sensor connector that intermittently drops the signal.
Carbon fouling on the sensor tip can skew readings without setting a hard fault, so always inspect the sensor element during diagnosis.
The EGR temperature sensor on many Nissan engines shares a ground with other sensors; a bad ground can set P1401 along with other codes.
After replacing the sensor, perform an EGR system readiness test with a scan tool to confirm the ECM sees a plausible temperature change when EGR is commanded.
Some Nissan models use a combined EGR temperature and pressure sensor; ensure you are testing the correct component and circuit.

Can I keep driving with P1401?

You can generally continue driving with P1401, but avoid prolonged idling and heavy acceleration until repaired, as improper EGR flow can increase emissions and slightly affect engine performance. If the check engine light flashes or the engine runs poorly, stop driving and seek service.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.