P203D - OBD II Trouble Code

Our automotive experts have put together the following information about the P203D diagnostic trouble code. We've provided the common symptoms that occur when this code is set along with the frequent repairs that address the issues related to the P203D code.

OBD II Fault Code

• OBD II P203D

OBD-II Code Diagnostic Trouble Code is defined as a Reductant Level Sensor Circuit High

Diesel Exhaust Fluid (DEF) is used to assist in converting leftover exhaust particles to harmless gases. In order to burn off those particles, the temperature of the exhaust system needs to increase. The injection of DEF Fluid into the exhaust stream brings Diesel Particulate Filter (DPF) up to temperature. The system is then able to convert harmful NOx to Nitrogen, Carbon Dioxide, and water. The Reductant Catalyst (SRC) was added to further reduce any NOx that was still in the exhaust stream. The Reductant Level Sensor tells the engine computer (PCM) how much DEF is left in the tank. If the PCM detects an implausible signal from the Reductant Level Sensor, code P203D is set. This sensor is usually built into the Reductant Tank.

Common Problems That Trigger the P203D Code

• DEF tank is damaged