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Our automotive experts have put together the following information about the P20B3 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 P20B3 code.

OBD II Fault Code

  • OBD II P20B3

    OBD-II Code Powertrain Control Module (PCM) failure is defined as a Reductant Heater Coolant Control Valve Circuit Low

    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 Tank Heater heats the DEF to prevent the fluid from freezing. If the engine control module (PCM) detects the Reductant Tank Heater is not operating properly, it will set code P20B3.

    Powertrain Control Module (PCM) failure Symptoms

    • DPF regeneration may not occur

    Common Problems That Trigger the P20B3 Code

    • Powertrain Control Module (PCM) failure
    • Reductant heater and sender assembly failure
    • Reductant tank heater control module failure
    • Wiring issue
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