OBD II Fault Code

  • OBD II P20F4

    OBD-II Code Extremely cold outside temperatures is defined as a Reductant Consumption Too 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. If the system does not use enough DEF, code P20F4 will be stored.

    Extremely cold outside temperatures Symptoms

    • DPF regeneration may not occur

    Common Problems That Trigger the P20F4 Code

    • DEF contamination
    • DEF injector failure
    • Extremely cold outside temperatures

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