P204B - OBD II Trouble Code

Our automotive experts have put together the following information about the P204B 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 P204B code.

OBD II Fault Code

• OBD II P204B

OBD-II Code Powertrain Control Module (PCM) failure is defined as a Reductant Pressure Sensor Circuit Range/Performance

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 was still in the exhaust stream. The Reductant Pressure Sensor is used to monitor and control the amount of DEF the Reductant Pump is putting out. If the Reductant Pressure Sensor sends back an implausible signal, code P204B is set.

Powertrain Control Module (PCM) failure Symptoms

• DPF regeneration may not occur

Common Problems That Trigger the P204B Code

• Powertrain Control Module (PCM) failure
• Reductant pressure sensor failure
• Wiring issue