P0031 NISSAN - HO2S11 Heater Control Circuit Low
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 harness is open shorted to ground
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse
- Faulty Engine Control Module (ECM)
For Nissan models 2005 and up see: P0031 Nissan
There is a Nissan service bulletin for the following models:
2002 Nissan Sentra
2002 Nissan Altima
2002 Nissan Sentra and Altima Factory Service Bulletin OBDII Code P0031
Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.
The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
Any information is appreciated. Thanks