Nitrogen Oxides (NOx) Module
The NOx module monitors the NOx sensor and controls the NOx sensor heater element. The NOx module communicates with the PCM through the high speed controller area network (HS CAN) to report NOx concentrations, oxygen (O2) concentrations, and NOx sensor system concerns.
The NOx module consists of a microprocessor, RAM, ROM, EEPROM, heater driver, and temperature sensor. The EEPROM stores the module calibration. The heater driver supplies a pulse width modulated (PWM) voltage to the heater portion of the sensor to maintain operational temperature. The microprocessor processes all of the inputs from the sensor and communicates the information to the PCM. The temperature sensor in the module is used for compensating the temperature dependency of circuit components and for module and sensor rationality checks.