Possible causes

– EGR Temperature Sensor harness is open or shorted
– EGR Temperature Sensor circuit poor electrical connection
– Faulty EGR Temperature Sensor
– Malfunction of EGR function, EGRC-BPT valve or EGRC-solenoid valve
– Blocked EGR passages

When is the code detected?

An excessively low voltage from the Exhaust Gas Recirculation (EGR) temperature sensor is sent to Engine Control Module (ECM) even when engine coolant temperature is low, or an excessively high voltage from the EGR temperature sensor is sent to ECM even when engine coolant temperature is high.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1401 NISSAN Description

The Exhaust Gas Recirculation (EGR) temperature sensor detects temperature changes in the EGR passage way. When the EGR valve opens, hot exhaust gases flow, and the temperature in the passage way changes. The EGR temperature sensor is a thermistor that modifies a voltage signal sent from the Engine Control Module (ECM). This modified signal then returns to the ECM as an input signal. As the temperature increases, EGR temperature sensor resistance decreases.
This sensor is not used to control the engine system. It is used only for the on board diagnosis.