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OBD II Fault Code

  • OBD II P20A9

    OBD-II Code Powertrain Control Module (PCM) failure is defined as a Reductant Injection Air Pressure Control Valve 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 was still in the exhaust stream. The Reductant Pressure Control Valve allows excess air to be vented outside the Diesel Particulate Filter (DPF) System. If the valve fails to operate as requested, code P20A9 is stored.

    Powertrain Control Module (PCM) failure Symptoms

    • DPF regeneration may not occur

    Common Problems That Trigger the P20A9 Code

    • Powertrain Control Module (PCM) failure
    • Transmission pressure control valve failure
    • Wiring issue
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