P204B OBD-II: Reductant Pressure Sensor Circuit Range/Performance

P204B Severity

Urgent

Should you fix P204B yourself?

Identifying an OBD code is just the start of a complete diagnostic routine. Most trouble codes are caused by a sensor reporting a value that is out of range. Just replacing a sensor may not fix underlying issues. Be sure to understand the code, the part or system in your car that the code refers to, and the risks of delaying professional repair.

Proper diagnosis will save you time and money on unnecessary repairs.

Urgent codes indicate immediate action is necessary. These are urgent and significant malfunctions that can cause severe damage to the vehicle or harm the driver and passengers.

Schedule Diagnosis

What causes OBD-II fault code P204B?

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.

Need a P204B diagnosis? Trust our experts.

RepairPal Certified shops provide expert diagnostics and repairs with transparent upfront pricing and a minimum 12-month or 12,000-mile warranty on all services.

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
RepairPal Car Genius

Ask our experts about P204B.

RepairPal Car Genius™ is a free resource for vehicle owners seeking advice on maintenance, auto repair, shop inquiries, estimates, and finding a trustworthy repair shop in your area.

 Auto Repair Expert Auto Repair Expert

Call us at 877-913-1554

Available 9am – 6pm ET Monday through Friday

Call Our Experts