P204C

DTC P204C Diesel Exhaust Fluid (DEF) Pressure Sensor Circuit Low Voltage

Circuit Description

The DEF pressure sensor is internal to the DEF supply pump and it detects DEF pressure in the backflow line between the main filter and the one-way valve. The DEF pressure sensor converts the pressure into a voltage signal, and sends the signal to the DEF control module. The sensor has the following circuits.
- 5 volts reference circuit
- Low reference circuit
- Pressure sensor signal circuit

The DEF pressure sensor provides a signal to the DEF control module on the signal circuit, which is relative to the pressure changes in the backflow line. When the DEF pressure is low, the DEF control module detects a low voltage on the signal circuit. When the DEF pressure increases, the DEF control module detects a higher voltage on the signal circuit. If the DEF control module detects an excessively low signal voltage, this DTC will set.

Condition for Running the DTC

- DTC P060B is not set.
- The battery voltage is between 10 to 16 volts.
- The ignition switch is ON.

Condition for Setting the DTC

- The DEF control module detects that the DEF pressure sensor signal voltage is less than 0.25 volts (-27 psi [-188 kPa]) for 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 and fail-safe controls. 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 an intermittent condition is suspected, refer to Intermittent Conditions in this section.

Test Description

The number below refers to the step number on the Circuit/ System Testing.
3. If the DEF pressure sensor signal circuit is normal, voltage level high DTC P204D will set.

Circuit / System Testing DTC P204C