P2223

DTC P2223 NOx Sensor Circuit Open Sensor 2

Circuit Description

The NOx sensor 2 is installed to the rear chamber of SCR catalyst housing and it measures the concentration of NOx in the exhaust gas after NOx conversion at the downstream of SCR catalyst. The NOx sensor 2 consists of the sensor element and the sensor control module. The NOx sensor has the following circuits.
- Heater circuits
- NOx detection circuits
- Oxygen (O2) detection circuits

If the NOx sensor 2 control module detects an open circuit on any of sensor circuits, the NOx sensor 2 control module will send a message to the DEF control module via the controller area network (CAN) communication bus and sets this DTC.

Condition for Running the DTC

- DTC U029E is not set.
- The battery voltage is between 11 to 16 volts.
- The ignition switch is ON.
- The engine is running.
- The NOx sensor 2 heater ON time is longer than 100 seconds.
- The exhaust gas temperature (EGT) 3 is more than 19 °F (-7 °C).

Condition for Setting the DTC

- The DEF control module received an open circuit message of any of the sensor circuits from the NOx sensor 2 control module longer than 3 seconds.

Action Taken When the DTC Sets

- The DEF control module requests the ECM to illuminate the MIL. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
- The DEF control module and the ECM apply defaulted warning actions. Refer to Default Action and Fail- Safe List.

Conditions for Clearing the DTC

- Refer to DTC Type Definitions for Conditions for Clearing the DTC - Type A or Type B.

Diagnostic Aids

- If this DTC is being present and error status indicates Short Circuit, go to DTC P2224
- If an intermittent condition is suspected, refer to Intermittent Conditions in this section.

Circuit / System Testing DTC P2223