P203B

DTC P203B Diesel Exhaust Fluid (DEF) Level Sensor Performance

Circuit Description

The DEF level sensor with DEF tank temperature sensor is installed to the DEF tank. The DEF level sensor consists of the float and the sensor tube. The float with a magnet is installed to the level sensor tube. In the sensor tube, there is a circuit board that the lead switches with different resistance are built. The DEF level is determined by a combined resistance value where the lead switch built on the circuit board is switched by a magnetism provided from the float installed to the sensor tube. The IP cluster receives the DEF level signal from the DEF control module via CAN communication bus. An expected DEF level change should be detected under a normal driving with DEF consumption that is calculated from the amount of DEF injection. The DEF control module detects this DTC if the DEF level sensor signal appears to be stuck compared to an expected signal change under normal driving.

Condition for Running the DTC

- The battery voltage is between 10 to 16 volts.
- The ignition switch is ON.
- The engine is running.

Condition for Setting the DTC

- The DEF control module detects a change in the DEF level too small compared to a calculated DEF consumption amount. This indicates a stuck DEF level signal.

Action Taken When the DTC Sets

- The DEF control module requests the ECM to illuminate the SVS lamp. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type C.
- 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 C.

Diagnostic Aids

- If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
- A sticking float movement will set this DTC.
- Use the Level Sensor Height vs. Resistance table to test the DEF level sensor at various height levels to evaluate the possibility of a skewed sensor.
- DEF level sensor may have an intermittent open somewhere in the operating range.

The DEF Tank Level parameter on the scan tool indicates 18% at the bottom (empty level) and 99% at the maximum level.

Circuit / System Testing DTC P203B